Vauxhall Frontera - can you help please?

I've just acquired a 1993 K-reg Frontera 2.4i, and I have a couple of
questions which you might be able to help me out with.
1) Is there a manual release mechanism for the tailgate? The switch on
the dash doesn't work (by the way, any ideas where the problem might
lie?) and I can't see any other way to open the thing! I can open the
glass, but not the lower part of the door...
2) Can anyone tell me what the little box of electronics underneath the
central console arm-rest is?
Any help / suggestions gratefully received...