@nick Yeah, but then even the surveys are chargeable. As it is, I had a plumber to the property doing other work, and he quoted (based on being there) for the boiler option.

IIRC both heatpump guys wanted paying for the survey (which is fine, and possibly refundable in some circumstances).

Intuitively I really would prefer, right-first-time fit a heatpump. With the sad reality of the situation, it's looking likely a boiler will be what we'll do.