Well after all the problems I had getting my rev 5.43 board to work in my A1200 I decided the board was broken and bought a rev 5.44.
BUT I still have the same problem so I guess its not the board afterall.
Whenever the board is put in I just get a red screen and and the power LED flashes a few times (about 10 times!) then the system reboots.
I've checked everything I can think of now, the power seems to be okay, I've checked the connector, checked the board isn't shorting out etc.
Any suggestions? Anyone near Nottingham want to try one of the boards in their A1200 for me? (my A1200 still works fine so I doubt it'll cause any damage)
:-(