

You cannot get a grant for a hybrid heat pump system (for example a combination of gas boiler and air source heat pump).
I think it just requires you to have a heat pump for all your water and heating. There appears to be pumps that do both, (mentioned in this article) but that’s more research than I can get away with while ‘working’.
Even if we ignored the immediate collapse of the world economy, if you were starting from scratch how would you get anyone to take risks and put money/time into creating a business?
Even if people did decide to do it, no banks would be able to lend to you (what banks? They need a massive amount of money to start) as they would have absolutely nothing as collateral.