I have travelled 9 times to Hurghada over the last 5 years staying several times at both the Grand and Grand Resort and once at the Marriott. In my experience there are no hotels which are 'mainly Brits' in Hurghada - in fact the British are very much in the minority although it is becoming more popular.
I found the Marriott to have a very balanced mix of nationalities who co-existed harmoniously, the clientele consisting mainly of couples or friends holidaying together. The hotel is generally sold on a B&B basis and the drinks and food are very expensive for Egypt so it does not attract the type of Russians who have the (much deserved) reputation for over indulgence and bad behaviour. However, although I enjoyed it there I was disappointed the hotel did not seem to live up to my expectations from reviews - I found it over-priced and did not care for the area immediately around the hotel. The beds, however, are the most comfortable I have ever slept in!
My favourite hotel is definately the Grand Resort (I have stayed many times at the Grand but according to recent trip advisor reviews the accommodation now leaves a lot to be desired). The clientele is predominently German but we had no issue with this at all, in fact if anything it serves to keeps standards up. Admittedly some could be more polite to staff but there was no sunbed hogging at sunrise or us and them mentality. The hotel is in the pedestrianised area of Hurghada just a couple of minutes from the Hard Rock and shops, bars, restaurants and pharmacies immediately on hand.
Hope you find what you are looking for and have a lovely time when you go.
Regards, Caro