Hannants have a superb range, but you don't have to go there for your mail order stuff. I can particularly recommend SBX models who will send out any paint order without you having to buy a model. Free postage too! Their website is:
http://www.sbxmodelshop.co.uk/default.htm
Or you can always try fellow website member Squiffythewombat's shop:
http://www.semodels.com/
Don't forget to post pics when you're done.