Creaser - I think the Hemel fire was bigger in that it went up to 20,000ft but same radius.
What I find unsatisfactory about the TRA process is that DAP who vet, process and then issue them as Notams do not, I suspect, have the formal right to question the dimensions.
This TRA, and many previous ones, are quite evidently designed to keep the newsgathering aircraft out. If noise were the issue, and it can be of course, (e.g train crash or building collapse where people are trying to listen for sounds of survivors) then the height limit should be the same as the radius.
If its protection for police/ambulance aircraft then 2miles and 2000ft should be ample.
Hey ho, to whom do we complain about all this? Oh yes, the Police themselves!