Again, in retrospect, a boarding school like Eton, Harrow or Winchester would have better suited him and if not those then an Andover, Choate, Exeter et al.
The parents I met at Westminster Great School had 1 thing in common: a dedication to the impotance of education for their child. This was a good thing to share in common.
Other than that, there were as you would expect tons of people from central London with very diverse and international backgrounds. There were very (very) wealthy families, yes, but also families where the husband is a GP and it was a mighty struggle to send their child to Westmisnter.
Then in Sixth Form you get the parents from Hong Kong and so on (there was a chat with all of the China kids on it called "Eastminster" which is kind of funny) and they sort of stuck together the few times they were here.
I'd definitely not send him there again as they are now taking girls in fifth form, and I am really against this. It will change the school inexorably. The Under School is done for.