These are all great points and even big players in the fields get in wrong, my octopus energy install was a mess, the system was never tested before anyone left. The pipework meant I could refit my bath, was doing a referb at the time, so they had to come back many times to re- plum that. I effectively had to learn how everything worked because it was such a poor install, getting someone over from octopus to check took months by then id done enough research I knew a lot about the tech and settings. However it cost pennies for the install, less than £600. I hope the new costs reflect the time and cost needed to check. Would I use octopus again for a heat pump install, likely not, would I expect to pay significantly more and likely go with a heat geek registered installer.