If yours works like mine, Stu, the next one you open ALWAYS verifies your previous beliefs.........
I will openly admit, here and now, that I do NOT use a "spell checker" of any shape or form. If its wrong, then my brain, the alcoholic beverages or my typing are at fault. Nowt else!
O/P - I`d be going for a communal heating supply - including DHW on demand - to keep the supply requirements down. However, you`ll still need an upgraded supply mate. I wouldn`t necessarily go with 3 phase - a single phase, 3 wire, 2 head system (I know the name for `em, but my friend "ms. Artois" has hidden the name from my intelligence centre) ( begins with "A" though)
HTH