Tea in England

I am a life long tea drinker (English) but a newcomer to this group. I live in a large town 220,000 population & have a good range of blended teas to choose. The unusual thing is that after reading about the teas drunk by people on this group & searching the shops I find that we don't have a very large selection of individual teas. Perhaps that is because we are half way between two large cities. (20 Miles each side. Anyway I purchased some Twinings Assam from the Bramaputra valley. This is an excellent tea but perhaps because of my English tastes I prefer it with milk. By the way I see a lot of letters used after tea types on the group. Is there a reference to what they stand for anywhere? Regards,

-- Dave Croft Warrington England