With the highest terrain in the UK of approx 4406 a common TA of 6000 feet (in line with that of the LTMA) is long overdue. I have never understood all these inexplicable disparities. A TA of 3000 feet in the open FIR with terrain above that is absolutely outrageous. Whoever implemented that should be shot. That is, if they haven't suffered from CFIT already.