If you have a dig round the various UK based online homebrew shops, you'll see a few different makers stuff out there.
I used to use whatever, but then learned that it's easiest to stick to the Lalvin brand stuff.
Now, it is available, but only the "usual suspects". Which is the ones that they routinely sell themselves in home brew sized packs.
The actual maker is Lallemand (I think they're based in Canada, but they're multi-national), which
from this link, you'll see that they make a massive range.
The "usual suspects" I've mentioned are EC-1118, K1-V1116, D47, 71B-1122 and RC-212. They've also recently started offering another one - QA23 I think it's called.
I used to use my local home brew shop, but recently because of work (actually I deliver in their area quite often and I can park an artic outside) I've been using
this place in Aldershot. Not really your area but they do keep an excellent range and yeast packs, only being small, I'd have thought that if you rang them, they could stick 2 or 3 packs in an envelope with just a stamp on them.
There are a few places that keep some of the liquid yeasts you will see mentioned as well. I've only tried the ones from Wyeast so far, and the dry mead yeast is fine, but their sweet mead yeast (wyeast 4184 I think it's called/coded) is a pain in the arse - finicky as hell to use, can get stuck easily, or even just doesn't start - but that might be more about shipping/storage etc (it has to be kept chilled etc). Either way, it's not cheap, and as I've had problems the 3 times I've tried it, I'll stick to the dry packs. Much easier to work with (irrespective of what those who make beers say).
If you don't mind the mail order thing and you can work out a couple, that sound good to try,
then have a look here ! I can only presume that they are repackaging, as there's no way in hell that Lallmand are doing most of those in small, home brew sized packs.
Ok, so with that lot in mind, some of the things that you will find, using the "usual suspects" for an example, is that while there's a massive amount of info available about the lallemand/lalvin products out there, they do, when it comes to meads, have a few things that we've found and that need to be bourne in mind when you're making your meads.
The descriptions of characteristics at the
Lalvin list site, are, I presume, from their product development and that would have been done mainly using grape musts (they're wine yeasts so that's a reasonable presumption to make, I think).
So, EC-1118 is a champagne region isolate (think that's correct - from memory). It's a good yeast, but does seem to blow a lot of the volatile aromatics out the airlock, which seems to have some impact on the more subtle flavour elements - which might not be an issue, but if you've gone out your way to obtain a nice varietal honey, then maybe you'd want to think on which yeast you'd be using.
D47 - we've found that with honey musts, despite them saying that it has quite a wide temperature range, above 21C/70F, it can produce fusels, so is best when kept a little lower on the temperature for the actual ferment.
71B-1122 - has some excellent properties for meads, but also for fruit based batches. It, apparently, can metabolise up to 35% of the malic acid that is found in some fruit (both in grape and more so apples, but other fruit too - to follow that some, you'd have to read up about malolactic fermentation, which is a specialist method of changing/reducing acids - it can have a downside, but for now I'll leave that). It makes some good meads that are "ready to drink" (that is relative.....) sooner (meads, especially traditionals, being known for not being so nice when they're young). It also has a reputation that it's not known to be good for "sur lie"/batonage ageing i.e. ageing on the lees, again that's a specialist method, that imparts certain properties to a wine/mead - you can find more about that with a bit of searching.
RC-212 - now that makes a good brew, but is known to be more needy when it comes to nutrients i.e. you'll see that people consider it a nutrient hog. One of the biggest reasons for me preferring the Lalvin range, is that they publish more data about their products than any other maker - and that includes their yeast nutrients. If you look at my blog, last year I posted a link to an article by the great Ken Schramm (author of "The Compleat Mead Maker" book), from Zymurgy magazine. It does get a bit on the "sciencey" side, but explains a fair bit about the kind of levels of nutrients we should be using. Some like to be very "anal" about measuring stuff, down to the enth degree, and while that's helpful in some ways, it doesn't help people get it right.
With RC-212, being or considered to be, a nutrient hog, you could just as easily, add a bit more nutrients and then just monitor the ferment a bit closer. One thing it's known to be excellent at, it colour/pigmentation extraction and preservation, so yes, it's a very good yeast to use for fruit batches that use red/black fruit. It seems to do a better job with the dark fruit at keeping the colour and aroma, so IMO worth the effort for elderberry, black berry, blue berry, currant, etc type batches.
K1-V1116 ? now that is a very good "all purpose" yeast for meads. It will do high alcohol (18%), low nutrients, it has the "killer factor" where it will become the dominant yeast - presumably it either overcomes wild yeasts often found on fruit, or it's just very competitive, it makes for very good traditionals and if you use the presumption that you will need to age a mead once it's made, then yes, it ages beautifully.
I can't say about the QA23 as I haven't used it yet and it seems it's only been produced in home brew packs since some time last year (as in 2013 - that was when I first started seeing adverts for it).
Take that lot for what it is, but if you have a look around, you'll find a lot of mention about Red Star yeasts - see how much detailed info you can dig up about those, the same applies to the Vintners Harvest range - the ones packed for UK companies, like Youngs, the info seems even more scarce, as is the stuff about the Gervin range (now supplied by Muntons).
That's not to say that they don't make good meads, they likely do, but I have only tried some of them (not found anywhere that does the Red Star range here, that came from the US).
Hence I just like to go with the ones I can get the best info about so I can make the best judgement for whatever is going in the batch I'm planning at a given time.
Hope that helps you a bit. As i've mentioned before, I don't know what is likely to be available locally to you in NI.......
{edit} - P.S. you could of course, using the Lalvin information, just use the yeast depending on what kind of wines you would normally like i.e. check out the regional info, then use them accordingly. EC-1118, D47 are mainly from white wine regions, K1V is mostly Red, as is RC-212, haven't looked up the region for 71B and QA23........ s'up to you really