In message , Mike Halmarack
writes

Seems like a fine opportunity for combined roofing and solar heating
panels, depending on your orientation. Good luck with the calcs.

Thanks.

East/West so OK but...

With a largish river 20m away I'm more inclined to a heat pump.

I don't know if o/p temperatures would be high enough for under floor
heating but I will bear it in mind for any future change of use.

regards

--
Tim Lamb