If you intend doing regular RTW trips it would pay you to start out of Bangkok
Buy a oneway ticket to Bangkok and book a RTW with Rani at Chawla Travel The Baht is low against other currencies so it is cheaper out of there even after the one way from LHR Use the last sector back to Bangkok to start your next trip Chawla are also the biggest Lufthansa agent in Asia and have the best Lufthansa fares anywhere if Munich is your bag With CX doing its work to rule / possible strike thing OW is not the way to go through HK at present so beware