I’m ready when you are:
A. Why wouldn’t you want to feed surplus to the grid. The UK solar industry worked really hard in the early 2000s to get remuneration payments for self-generators. Payments are a form of offsetting, so you when over producing, those financial benefits you during the winter months.
B. The cost will be negligible really, as the cost of scaffolding would be about the same cost of the A frame construction of a ground mount. The shorter the wiring distance the better.
C. An evacuated tube system will cost around three grand, compared to a PV heat converter that costs a few hundred quid.
Hope this helps.