The Apple store is about 30 miles away. I’m sure, if I get up early enough to avoid all the cows being taken for milking, I can catch the daily bus out of the village to the big City. 
I’ll try and pop in early next week as the weekend will probably be hectic. It’ll be interesting to hear what they say, especially if it is the OS. 
In the meantime I will remove Radium, Litte Snitch and boot without extensions to see if that makes any difference.
Book yourself a “genius” appointment first … then you can be sure you can get seen.
Which is the “big city”?
Mr X
Yep, that was my understanding. I also understood (perhaps misunderstood?) that you had copied across data from a previous machine onto your new install. I don’t recall mention about what method you used to copy that data.
The issues seem unusual for plain-wrap Yosemite. This is not to say that your experiences are unique, we know that other people experience them too, but they still remain the exception. Hence the suggestion that software or hardware may be the true gremlins. The steps suggested — Jaysen’s shift-boot (easy, I’d definitely do that as a first step) and then, if necessary, a secondary clean-install (time consuming, but thorough) — should help identify if the issue is most likely to be OS, software or hardware based.
For the record, I’ve had experience with buggy hardware. Took three years to sort it out, but this was before an Apple store opened an accessible distance away. Once it did, it only took their Geniuses 2 or 3 goes before they decided to replace my ageing machine with a brand new MBP (AppleCare was worth every penny on that machine). I wouldn’t wish 3 years of buggy hardware on anyone – it’s worth investigating now.
There has been many complaints from the upper echelons of the Apple geekosphere that Yosemite is the result of a clear downward spiral in terms of software craftsmanship, and this is worse than any hardware changes:
marco.org/2015/01/04/apple-l … igh-ground
daringfireball.net/linked/2015/0 … igh-ground
furbo.org/2015/01/06/death-by-a-thousand-cuts/
and a good description of the discoveryd woes:
OK! Y’ can all relax now. I’ve just got rid of the Yosemite septic tank, and connected to a proper sewer. 
Classic … eh?
Still got the ‘Idiots’ Guide To OS 8.5’ somewhere 
Ahh … there y go! 
I never actaually copied any data. All Apps were newly installed or downloaded direct from source. I then have several external drives: 1, Work . 2, Music. 3, Media. 4, Scratch disc.
Strange to most I expect but I tend to keep the Mac for apps only. Everything else goes on drives.
Cardiff. There is a nearer City but it doesn’t have an Apple Store. Wales has only two. So if you’re in the North you’re pretty much out of luck. 
I have been trying to book an appointment but for some reason every page on the apple site loads fine until you get to the booking section. I have been trying most of the day so I’m giving up and am instead going to sort out a replacement via Amazon. I’m sure that will be quicker than trying to book the appointment.
lol I still have a copy of the 1996 Maclopedia with a CD-Rom that include fully hypelinked TEXT! 
I also still have my Mac Plus with http://www.cultofmac.com/122408/signed-by-steve-jobs-co-signatures-inside-the-original-macintosh-case/
So… new Mac, same issues. Wifi didn’t work initially, needed to upgrade. The redraw issues in iTunes 12 are still present. The only slight difference is, instead of the ‘fuzzy 8bit style’ screen on wake up, I now occasionally get a black screen which means I have to force shut down as there seems no way to get the monitor to sense the Mac Mini is awake. This is obviously more of a pain than the fuzzy screen was. I haven’t installed Little Snitch or Radium so they’re out of the equation for sources of the problem. Guess I’m going to have to pin my hopes on 10.10.4.
10.10.4 … today, along with iOS 8.4.
We’ll soon see…
If it is released today, I hope it fixes the issues you’re experiencing.
If it is not released today, get the beta…
beta.apple.com/sp/betaprogram/welcome
10.10.4 just released… fingers crossed.
Thanks. Just looked and it’s available. So will install it now and try it out for a while.
While it’s downloading I’m just reading through the list of stability and compatibility issues being addressed. Lo and behold all my problems (except the iTunes redraw issue) are being sorted… hopefully… fingers crossed.
iTunes itself hasn’t been updated in OS X 10.10.4.
Still on iTunes 12.1.2.27 at the moment.
iTunes 12.2 (with Apple Music) is expected today…though no sign of it yet. Perhaps that will also improve things for you.
Why does that fill me with dread?
I did see an article on reverting to iTunes 11. I may try that instead.
10.10.4 installed so will give it some time and come back with a few answers.
Just try shuffling a few degrees t’ left or right, and view it from a slightly different perspective.
Hope this helps. 
Works for me.
Curet amici mei
Galileo
I meant the method … not that crock-o-shite, iTunes
Here’s a whack question…what kind of electronic devices are around/near the computer? Wifi issues could be explained by any number of things: drivers, a cordless phone on the same bandwith, lead paint, and excessive use of cinder block/brick in the building construction. Have you tested the outlet that you’re plugging the computer into? Power issues (whether by bad power, brown outs, or a bad PSU) can cause a host of strange issues that don’t seem to be connected. (For instance, when I had a power supply go, first the hard drive went, then the video card, and right before it gave up the ghost in a puff of smoke, it was looking like bad RAM, as well.) The things you describe as being wonky on your computer are all things that are power-intensive. (Video, wifi, etc.)
Hi Garpu, wifi is indeed a strange creature. Unlike radio waves it really doesn’t really like going through anything and the signal quickly drops downward. But I had an older mac in the same position so knew the location wasn’t an issue but thanks for the thought.
The good news, depending on your point of view, is all my issues have been resolved by the latest update 10.10.4. The bug fix list Apple released, to accompany the update, had all my problems listed. Discoveryd is no longer. They have also fixed an issue that prevented some external displays from functioning properly. Strangely the redraw issue in iTunes also seems to be resolved. 
Thanks to everybody for their input and ideas. I’m glad my problems have been solved by this update. However, I can’t say I’m very impressed. Having been out of the loop for a while, sticking with the ever faithful Snow Leopard, to have two new macs have major issues straight out of the box is pretty appalling. Especially knowing all these bugs were pointed out to Apple before release and they chose to ignore them. It’s all too easy to blame RAM etc as we’re used to the Apple, of old, being on top of things. I guess with Apple having their fingers in so many pies something’s got to give. On that note I think Apple has indeed become the new Microsoft.
Nahhh! y’re only saying that cos …
My iTunes redraw issue returned once I reconnected the Touchpad so… Having been offered the iTunes 12.2 update this morning I thought I would check out the news first, for anything iTunes 12.2 related, before taking the plunge. Boy am I glad I did. Just thought I’d post this incase anyone else, with a love of their music library, is thinking of upgrading.
http://www.macworld.com/article/2943723/why-you-might-not-want-to-upgrade-to-itunes-12-2.html
I’m surprised this is considered a “first”. I regularly have this issue with iTunes upgrades. Entire albums go missing but can’t be re-added. Happens on every upgrade. I really wish there was a real alternative to iTunes.
I wasn’t meaning the renaming of songs, that’s been an issue for a long time. I’ve always stopped iTunes connecting. It was more the fact your songs could be replaced by lower quality or DRM enabled music. Since iPods, and iPhones, don’t have the ability to play Apple’s own high end lossless format I’ve had to buy a different player. DRM files wouldn’t play on it.