Thankyou for all the advice - certainly food for thought - and apologies for precipitating an argument!

On reflection on what you've said @derek-m I am now leaning against the idea of an ASHP at this stage.

To be honest two things got me thinking about this again recently - firstly an ill informed (in my opinion......we shall see) plumber saying they thought I needed to replace my 4 year old boiler (some nonsense (IMHO) about under floor heating needing higher heat output - from what Ive read this is likely to be the exact opposite), and thoughts of replacing our boiler now when I could 'future proof' against rising gas prices by moving to electric heating.

However as you say Derek, I'd need to achieve an average COP over the year of 4 at least to break even let alone save money (based on my current albeit very generous energy tariff....that wont last!).

I think for now I'll stick with gas and see what energy prices/ the cost of the pumps do over the next couple of years.

However your comments HAVE made me go back and have another serious look at solar on its own - and I think thats the direction Im going to head in - we ought to easily be able to use all the power we can potentially generate and break even in about 6-7 years based on current available electricity prices - so THANKYOU for focussing my mind! Less rush to get that sorted too seeing as theres no grants.....grrrr

@majordennisbloodnok  I am seriously impressed by the price you got your system for - was that a solar streets set up by any chance? I attended a talk by them here last year but as far as I can tell there wasn't really any take up which is a real shame. However EoN's packages dont seem too bad at present....

@robertoi PV on its own can be massively beneficial. Tied in with a battery and it can be even better. Last year with generation and energy savings I saved about £1800; £600 in generation and the rest from solar meaning I didn't need to buy power.

People seem to assume that buying PV adds cost. I've had my system two and half years and it's paid back 33% of the install costs. At the crazy unit rates this year coming, that'll be even greater. Adding as ASHP just means my heating and water bills will be around zero for 6 months of the year, lowered in 3 months and higher in the winter three months. However I am happy as it's an offset game.

For an FYI my solar and battery cost £11,800 and my ASHP (which replaced mains gas) was £5000 - but I'll get this all back in RHI. I am hoping my heating bills are a little lower. My energy use certainly is far far lower than it would be by burning gas and as such my CO2 will be dramatically lower.

@robertoi, no it wasn’t them. In fact, it was a partnership between Surrey County Council and Solargaps. The council got the public interest, Solargaps negotiated the bulk buy deal with the manufacturers and then they held an auction to find an installer to handle the logistics. The preferential prices basically brought the cost down to the point that I effectively got the battery for free.

Posted by: @majordennisbloodnok

@robertoi, no it wasn’t them. In fact, it was a partnership between Surrey County Council and Solargaps. The council got the public interest, Solargaps negotiated the bulk buy deal with the manufacturers and then they held an auction to find an installer to handle the logistics. The preferential prices basically brought the cost down to the point that I effectively got the battery for free.

My bad, too many companies with similar names. Not Solargaps but Solar Together. Apologies.