Bongo Fury

when i remove my second battery the central locking does not work on the alarm fob, anyone got any ideas

Is your second battery rigged as a leisure battery? if so, the central locking is usually put across onto that. If you have 2 in parallel, then it would suggest the voltage on the remaining one is a bit low. That's assuming the batteries in the fob are ok, which is porbably the case if it works ok with the second battery connected.