In the camper (2001 Ducato) I'm getting 14.36V when its idling but when the fridge is running on 12 Volt it occasionally cuts out, I can hear a relay in the distribution board clicking, this happens in traffic when the revs drop, as soon as the revs increase the unit cuts back in again. I thought that was a good voltage,What should it be pumping out? Any ideas? The battery is new btw, the leisure is a bit old but still seems to work OK. Just treated her to all new interior LED's today, that should help with the draw on the leisure battery. Good price in Norauto France, G4s at €6.99.

The regulator on the back of the alternator should maintain 14.00V under all circumstances. 14.36V isn't immediately lethal but it does shorten the service life of the starter battery. The leisure battery doesn't get the full charging voltage due to the long wiring and a diode.
Even at idle the alternator should be able to supply power to the fridge, so I would start by replacing the regulator.

If its the 120A valeo alternator the set point is 14.6V so 14.36 would be spot on.

Here is a clear explanation of car battery charging:
http://www.ratwell.com/technical/ChargingSystem.html

An alternator set at 14.6V and connected without a diode shortens the life of both the battery and the light bulbs. My Ducato has consumed 3 batteries in 8 years, my Kia Sorento of the same age had its original Korean battery replaced this spring because the engine didn't start within a second, like it should.
But it can be even worse, some Motorola alternators are set at 15V!!