Martyn, my thanks to you once again.

My trial system works nicely and seems to maintain a very even temperature within the room. There is also a satisfying motor whirring noise as the valve operates !

Like "autolog" I am (was) going to buy some more kit from Conrad but noticed that in your (English) datasheets there is reference to a company called www.housetechsolutions.co.uk (who happen to be about 2 miles away from where I live in Gloucestershire)

Who are these people and does anyone know whether they can supply kit directly ? Anything to do with heating-intelligence whose website is 'empty' since before Xmas ?