Well, my local library is part of a larger system, so I can get things from several counties without having to use interlibrary loan. But interlibrary loans are always a good option to try if your library doesn't have what you need.

I've seen Rosemary & Thyme, it's pretty good.

I haven't seen any Upstairs, Downstairs yet, but it's this huge classic, so I'll have to give it a try sometime!

But you totally have to see Jeeves & Wooster! And Lord Peter! (The Edward Petherbridge version is the only one I've seen, but they're perfect, so I haven't even bothered to see the Ian Carmichael ones!) Try interlibrary loan, but if you can't get them there, you could try DeepDiscount.com. They've got a pretty big British Drama section, and their prices are the cheapest I've seen. I got a lot of my DVDs from there.