Dometic toilet

Hi all 
The dometic 4050 toilet in my 2013 symbol packed up while away last week, no flush or lights on the little round panel. 

The main water pump is working, this shares a fuse with the toilet, there is a 7.5 amp fuse on the underside of the round toilet panel, it checked out ok.

Inside the toilet housing I found the 2 wires that supply the panel have crimped joiners in them so I nicked the insulation a little on what should be the live side of the joiners and tested for power but nothing there either. 

So I've now exhausted my electrical knowledge, has anyone come across this before? or have any suggestions as to what I can do next.

Thanks in advance 
Al