If the QNH was 1045 Milibars then FL25 would find itself some 3460ft AMSL and thus would be the transition level in the UK and would give a transition layer of 460ft.
Quite so, DFC ...... except in those parts of the country where the transition altitude is 4,000ft .... or 5,000ft ..... or 6,000ft!
DFC, I know you understand that, but pilotincommand is in serious need of some more bookwork before he adopts his nom de plume in anger.