I would like also to install a heater in my M26. Yesterday I was speaking with a MG owner, he consulted on this the Blue Water Yachts, and they recommended him to install a Wallas 1300 kerosene heater.
He is very satisfied now. He installed it on the wooden board btw the V berth and the head, with exhaust going right up and out and the fuel tank under the v berth.
Have you already installed another type of heater?