Hi
I am a Brit and speaking as a Brit I would say
if you're smart you choose a mixed compound if at least for the difference. You will get along with all the other expats whether they be westerners( english and non english speakers ) and even the Asians.

The point of Qatar is to meet different people and if you are worried that you have to meet or bump into difficult people you would rather avoid, then you are likely to do so by choosing a compound that feels right to you regardless of whether there are Brits or not.
I live in a compound that is a mix of westerners and a few arabs and even a gulf arab down the road. Most people do get along.

Snobbery and ignorance does exist for some people amongst all races here even the western expats ( white and black ). Qatar sometimes brings out the worst in people.

Go with your gut feeling when checking out a compound and you will be alright.