I am confused about how I go about getting a permit for two people (a British and a Swedish national) to visit Lhasa, intending to travel there by train. Is it possible to get a permit without having to have a tour guide? I don't mind going through an agency.
So far as I'm aware, it isn't currently possible. You can hire guides individually though.
I've heard from a couple of different people that permits to Tibet for foreigners are currently closed though, so you'd probably do just as well to call an agency (the big places all have English speaking staff as well) and see what the say. It's hard to find concrete information on these kinds of things, but the agencies are usually more up to date.
Hope that helps. Good luck with your travels.
No independent travel in Tibet since March 2008, and near impossible before that. Tibet has been closed in March every year since 2008 (preventing protests around March 10th , the failed rebellion and escape of Dalai Lama in -59) , and is closing as we speak .
Best way in is by train , esp. if you break up the journey one or two nights in Xining ( altitude 2300-ish). Use the extra oxygen outlets the first hours after Golmud
Lots of Tibetan culture outside Lhasa and the dotted line of TAR if permits won't appear - see here.