Geoff,
we’re having a setup from Nu-heat, they’re down in Devon, and a plumber who has done a load of work for me is a registered installer of theirs.
We’re in a detached house, and have a single 1.8 X 1.2 solar panel. It’s just been fitted today.
The boiler is a Worcester Bosch and is an external unit to free up space in the kitchen.
I also have a wood burner, but the plumber wasn’t keen on fitting it into the thermal heatstore as it’s effectively an uncontrolled heat source and there’s hassles with that. To be honest, I suspect the amount of wood I’d need to keep and season would be astronomical to make a back boiler worthwhile.
Heatstore is one of these http://www.nu-heat.co.uk/s.nl/ctype.KB/it.I/id.17092/KB.122/.f