Which fuse is for the handbrake warning light and warning signal ?

Daughter has to temporarily disconnect it as the switch under the
handbrake in the floor has broken and warning signal howls all the time.




 

There isn't such a fuse. The switch wires direct to pin 21 of the 32-way connector at the instrument cluster, the other side going to earth/chassis.

You should be able to simulate the handbrake being off by either shorting these wires together or just leaving the connector unplugged from the switch.