So we took the coach in to assess the cause of the fire and it turned out to be a frayed fresh water tank heating wire. The wire insulation had worn away and made contact with the metal underside of the chasis. Amazingly no other damage to electrical. We need a new fresh water tank, its beyond repair/patching. The heating tape has been plugged in this whole time, now we now. A costly rookie mistake, could have been so much worse.
Jason