Hi Pete,
Welcome on board!
I wanted to say something about culture shocks since you never left Europe; but that would be not appropriate since I've not been in Thailand yet - although I've spend quite some time in other Asian area's.
From your post I get the impression that you got a package tour. I did not. Just a plain airline ticket and I go when my nose brings me (ie where there is no rain).
A nice website to look at is
Bangkok Bob's guide to Bangkok Bangkok Bangkok
Have a lot of fun