Ive always gone for 'home' microwaves marine ones seem over priced.
I have seen boats with microwaves witha simple pull catch to open the door which swings open in anything other than flat water. Thats one of the first things I check for a proper closing /locked -into -position-push-button-to-open catch
Can't help with the suplier I'm afraid, but if it helps, I use a normal household microwave, which are lots cheaper as Haydn pointed out. I have an inverter fitted to my boat so I can use the oven when no mains power is available. Works a treat. I reckon you could pick up both inverter and microwave cheaper than a marine unit.
Does anyone know if the following test has any merit, to test a microwave for leaks it is said that if you put in your mob/ph and dial your no,your phone should not be able to take an incoming signal???
I've got a wopping 1500 watt inverter coupled to an independant deep cycle liesure battery. The microwave is 750watt, so the inverter handles it without a problem. The battery is attached to a battery charger that comes on when we plug in to the mains in order to keep it topped up.
We were watching the Southend airshow earlier this year and was anchored off shore for about four hours, we had the electric kettle, the microwave and a small toaster going on and off throughout this period with no signs of the low power alarm going off.
You could attach the inverter to your leisure battery on the boat which will then be charged by the engines I suppose. we've never bothered because this set up works fine.