In my country (Ireland) you more or less have to use professional installers for anything non-trivial if you want to get any sort of state grant/refund to cover

In my country (Ireland) you more or less have to use professional installers for anything non-trivial if you want to get any sort of state grant/refund to cover the outrageous costs (with VAT piled on top). I did a retrofit, I can't imagine how complex it might be for a self-build. I admit dealing with old housing stock is a complicated problem. it seems they want you to partake in the bureaucracy to keep the cowboys out, which is not unreasonable given the problem at hand.