Erm I stayed at a relatives in Thailand a few weeks ago and met some of their Expat friends. Anyway I started talking to this Thai dude who was at Uni in Imperial (cant remember course, something to do with computers and electronics). He said he spends most of his time hanging out with his Thai friends in Imperial (which is a London Uni, very multicultural so it doesn't surprise me!). Most top universities are seriously multicultural. I'm probably going to goto UCL and swop to mathematics, I need to be prepared to be in a class of Chinese students for example! LOL.
I dont think Alcohol will be a problem, aslong as you dont make out your better/superior than others cause you dont drink. Its your choice really, people wont mind aslong as YOU dont make a fuss out of it. People in the UK are FAR FAR more confrontational than people in Thailand, this may take some getting used to! Generally speaking you dont need to take off your shoes when you enter houses, and you certainly dont when entering shops etc. Sport is a big thing, bigger as far as I can see than it is in Thailand - especially Rugby and Football. Theres more fat & ugly people in the UK (on the girl front) - big generalisation but this seems to be the case, British food is more unhealthy than Thai food. Is it just me, but are most Thai's like the perfect weight lol? I guess i've only been here a month.
Out of interest what international school are you in. My relatives live in Samuk Prakan district outside of Bangkok, their children (age 16/13/12) go to the international school somewhere in Bangkok.