Bongo Fury

My handbrake warning light stays on most of the time when I'm driving, though the handbrake is definitely off.
Does this signify anything?

Rocketeeer

Yes your brake fluid level is LOW !
Even if it looks ok when you look at under the bonnet on level ground you will find that as soon as you hit a slope it will start warning you. Fill it up ASAP. The tank is centre left at the rear under the bonnet.

or there is something wrong with the switch under the centre console where the base of the handbrake is.

If the fluid level and the handbrake switch is ok check the servo vacuum switch.