Thetford Cassette toilet fridge - Fuse

I had the occasion to help a fellow Bushtracker owner who had a Toilet that would not flush.
The water pump inside the unit would not come on.
We read the operation manual but found not comments regarding the electric pump or any form of wiring diagram which could show how it is connected. We thought perhaps there is a fuse in the circuit. But no mention of this in the manual.
I started with my voltmeter and found that there was power at a small 2 pin connector under the unit (after removing the cassette of course). At least power was getting to the unit so it was not a fuse etc from the batteries. We looked every where but could not find a fuse or fuse holder so assumed the power just went direct to the pump via the microswitch which seemed to be working OK.
Next went inside the unit and pulled the motor out, The pump seemed free in its movement so went back ouside under the unit again.
Finally using a mirror and strong lamp, saw something resemling an auto (flat blade) fuse holder but no fuse !!!! Plugged in a 10A fuse and all was well again in the world of Bushtrackers.

It appears the fuse vibrated loose and fell onto the cassette. When it was removed for emtying, the fuse was not noticed and it disappeared with the rubbish.
The fuse is in such an awkward position above the cassette that this will surely happen again to someone. As there is no mention of a fuse in the manual, it can be a most annoying problem.

Regards
Kurt