Paul - its a Finnish Jaspi biotriplex boiler with a Swedish Ulma pellet burner married to a FInnish Jaspi 700 litre thermal store
more on the set up here
http://www.singletrackworld.com/forum/topic/anyone-on-here-know-anything-about-thermal-stores
geoff - IMO GSH isnt neccesarily a great idea because your are still pegged to electircity prices and at COPs of 3 or 4 and elec prices of 12-15p/kWh, youre still paying 4-5p /kWh for energy, which is what I pay for biomass and Im sure elec inflation is going to be higher than biomass of coming years.
You also get payments under the RHI initiative - mine's just going through certification, we'll see how much money I get for it, but I expect it wont be as much as was talked about a year ago.
FYI set up cost about £10k to install, including the thermal store but excluding the flue (£1300)