Sorry but can't find a link in B&Q site to the small heater ... and it is small ... wall or floor mount.
My boat is sitting in Latvia and winters here are a little cooler than UK etc. I have the Dimplex in the main cabin on low setting and the B&Q job in the fwd cabin on low to med. setting. Boat is warm, dry and taking actually little electricity to maintain it.
I leave the WC vent open (mushroom job) and the fore-hatch cracked ... the washboards have slit vents in anyway. So boat is nicely set-up.