Finalizing reservations for Sept trip to England - you have all been SO helpful so far! I want to make bus reservations and am a little confused - there are too many buses and routes ;-) We arrive Heathrow, want bus to Oxford. We'll get a taxi from bus station to our hotel (we're not renting a car until our last day in Oxford). Then a week and a half later, we're returning the car (in Oxford again) and spending the night before wanting to take the bus from Oxford to Gatwick.

I'm guessing we want 2 1-way tickets - do I need to book a specific bus or can we take "first available" (not sure how long immigration/customs/baggage will take, also probably want a shower in the lounge since we won't be able to get into the hotel ASAP)? Then our return, we want to book Oxford bus station to Gatwick, again 1 way?

How many bus companies are there? I'm on the National Express site and it's telling me some of the tickets they sell are 3rd party, but I'm not sure how to tell whose bus is whose and where to buy directly.