Sorry Seat 0A, you're right about IAH-AMS-LOS (except KLM have a lousy record for cancelling the AMS-LOS at short notice!)
The fact is, I work at LGW (for Nigel (BA)) and the "Houston Oilies" (as they're known with affection) have always preferred Gatwick - the one's we come into contact with either have business in London en-route, or ABZ.
Gordon Bethune (President of Continental Airlines) identified (a few years ago) that Gatwick's strengths lay with the Oil Industry connections with British Airways (Aberdeen, Baku, Lagos, Eastern Europe)
One by one, these routes are being shunted up the road to Heathrow - an airport the "Oilies" hate with a vengeance!
Bealine loves his job! He hates BA making decisions which adversely affect his clients!