Hi, I'm the retiredmartin that Northern Brewer kindly linked to in recommending the Coopers in Burton. I've retired and travel round the country and further visiting Good Beer Guide pubs. Blog is
www.retiredmartin.com
Great to see Martin chip in - for those who don't know he's probably my favourite of a wonderful group of bloggers that includes
BRAPA and
Pubmeister, blogging as they visit every pub in the Good Beer Guide. But they're much more than that - they're a chronicle of provincial Britain, where Uttoxeter and Burton are stars of the show and the big cities hardly feature. If you're interested in British pubs, do follow them.
Also
Boak and Bailey - their
Pubs of Boggleton is a long blogpost that is effectively a fictional summary of their
20th-Century Pub book which is probably a must-read for this kind of trip for understanding how the modern pub scene came to be as it is.
Des de Moor is working on an updated version of his London pub guide but it won't be out until February.
Anyway, I was loathe to say this myself, but you should pay attention when someone like Martin who has visited several thousand GBG pubs says this :
Manchester has, to my mind, the best collections of pubs and quality beer in the UK.
But I guess you have to make a bit of a decision whether your prime interest is in pubs or beer. And while it's true that some festivals can have indifferent beer - that's also true of some pubs, even GBG pubs, particularly on a Tuesday, but that shouldn't put you off going to pubs - and it's far more of a problem for festivals held went ambient temperatures are above cellar temperature. Conversely pubs in January suffer from lower turnover, which means either staler beer or reduced choice - I know one that goes from 5 lines in summer to 1-2 in January, although that's an extreme example.
Also festivals are a great opportunity to try lots of beer in one place, so will have more of rarer styles like mild, and that you know are at worst a couple of days old and Manchester is one of the good ones. It has people who know their stuff running it, puts (almost) all its beer through handpulls (a miracle of plumbing in itself), and is a bit more "sorted" than some other CAMRA festivals. It's unusual in having a dedicated beer from the wood bar (with Roger Protz leading a tasting on Friday, if you're quick), and the 100 Club bar (as in years, ie family brewers that predate Prohibition in US terms) tends to have classics that are seldom seen in cask like Owd Roger and Prince of Denmark.
I've never been to the Winter GBBF, I imagine it will be pretty well organised but may suffer a bit from the fact that it rotates round different cities so may not have quite the slickness of "permanent" festivals. But it will have more US-strength winter warmers and less pale stuff than Manchester!
I wouldn't get too down on London, it's not as irrelevant to the national beer scene as say New York, but is more the equivalent of say California. And it does have some wonderful buildings, and some great cellarmanship, even if the two seldom coincide. And most of your flights will go there, and from a China perspective I guess the V&A and British Museum are pretty much must-sees. No comparison on the neighbourhood pubs though - V&A is in a bit of a desert, whereas the Museum Tavern is a rarity in having Old Peculier on cask permanently (personally I'm less keen than USians seem to be) and the BM is not far from some of the classic gin palaces like the Princess Louise. And one can certainly think of multiple worthwhile pub crawls - Harp-Cheese/Louise-Mitre on the north side of the river, Borough Market is almost one in itself (Rake, George, Royal Oak etc) then the Bermondsey Mile of railway arch breweries. So don't worry (other than in your wallet!) about a lack of good beer in London, particularly if you're fitting it round other things.
The commercial galleries in London also have a fair bit of Chinese stuff, also worth mentioning the China museums in Bath and Durham (both a bit out of your way), and the contemporary China place in Manchester.
Again it depends what you're looking for, but Burton might not detain you for more than a day trip, once you've done the NBC and Coopers. It has a good hinterland of working-class pubs, that serve little else but Bass and Pedigree if that's what you want. January is not really the time to be going for country walks, but much of rural England has the kind of pub walks described above in Warwickshire.
FWIW Warwickshire might creep into my top ten for beery counties but it would probably be just outside. York is a great city in all sorts of ways, and has great trains to London (and a fun rail museum if that's your thing) but is a bit of a faff to get to east-west and may be a bit far out of your way?
I'm probably the wrong person to ask about pressure barrels, as I'm not so into the plumbing side of things - if I want cask beer I'll go to a pub and I'm happy to bottle my experiments. I'd say probably not, if only because it's a red flag for customs people to investigate further. Although Tesco's website has (used to have?) some brewing stuff, I'm not sure I've ever seen it in store - possibly in the non-food bit of their big stores, which is not somewhere I ever go. However there is a
Wilko on the high street of most of small-town Britain, and they have a good basic selection of brewing stuff.