Are all the concerts finishing about the same time ,about 11 o'clock or is it later?

It's an 11pm curfew at the venue and most big venues. I used to think it was because of the noise, particularly outdoor stadiums like Wembley and Twickenham that are in residential areas. But I doubt you can hear much outside the O2

I think the cufew is on the order of the Police as they dont want 20 odd thounsand people trying to get out of Greenwich when the tube has closed down.