If it was built in 1994, the board shouldn't have fuses/fuse wire. They should be MCBs. So you have to take off the whole front cover, & remove the wires to replace it.
REALLY don't recommend doing this yourself, as it can be stupidly dangerous if you don't know what you're doing (Being shot across the room in a ball of fire kinda dangerous). Thing is, if the shower used to work, there could be a wiring fault somewhere, or the rating of the MCB is fine, but it has just died itself (Not likely, but possible)
Sounds about time to call in a spark to be honest!