As you seem to live in the country have you considered a solid fuel cum
multi-fuel stove. I was in a similar situation to you 22 years ago
after buying a modernised Granite cottage in Aberdeenshire. Electric
storage radiators that were totally useless and a sort of open fire
that went right through an end wall to produce a fire in two rooms.
This was also useless as 50% smoke went to one room, 50% smoke went
into the other room and 10% went up the chimney. Yes that's 110% that's
how bad the ***king conversion was.

Anyway I bought a big cast iron Bonte ESSE Mark 4 Room/Space heater
with a water jacket that gave out 12kWatts. In 1983 that cost me =A3850
so Gawd knows what the same would cost now.

I had no experience in CH systems but I could solder (Electronics Eng.)
and I knew the priciple of a 'U' tube and that hot water rose to the
top. I did the water header tank and the HW cylinder myself. That's
simple. A local Plumber was removing a Banana skin from the neighbours
drain so I chatted to him and he looked at what I'd done and said all
was OK. I then popped the question about him doing the actual CH side
of things. This was September, he said I can't do anything until after
Christmas. He then sat down a drew a system on paper for me saying run
two 22mm. pipes a far as you can and 'T' the radiators across them. I
did exactly that and 22 years later the system has never even sprung a
leak.

I do burn Anthracite at about =A311 per 50kg bag during the winter months
and then any fallen Beech bows or whatever during the warmer months.

So basically learn how to solder/sweat a good joint. Learn the
principle of the 'U' tube and go for it yourself. It took me three
months to do my system but what a difference it made.

Two years later my neighbour got the Pro's in to do thae same to his
cottage. That cost him =A33,500 and......... AND two insurance claims for
damaged carpets.

IT JUST AIN'T ROCKET SCIENCE.

Chris.