Well not being in the UK it's tough for me to recommend - the only UK online shop I deal with regularly is Hannants (and sometimes MDC).
As far as acrylic brands...depends on what you're looking for. Tamiya makes excellent paints for airbrushing, but IMO the term acrylic is applied somewhat loosely.
For the "pure" acrylics, my favorite is Vallejo. Excellent pigmentation, they brush paint very well, and IMO they're easier to dial in with an airbrush than Lifecolor.
On the Bench: 1/32 Trumpeter P-47 | 1/32 Hasegawa Bf 109G | 1/144 Eduard MiG-21MF x2
On Deck: 1/350 HMS Dreadnought
Blog/Completed Builds: doogsmodels.com