The guy was on site the entire day, to be fair, but mostly because he had a nightmare trying to get the unit attached to the wall where I wanted it to go, because of crumbling mortar. I can't really fault the engineer who installed it, but yeah I was certainly taken advantage of. I wonder if it's even worse with the Andersen because they might figure "well he's spending over a grand already"...
Approx 4m of the cable was underground, but again I dug the trench already and even made good afterwards - all he had to do was run it in the crevice. The rest of it was inside an outbuilding, but free access in there.
EDIT: It didn't even occur to me until reading the above that they quoted for 11 hours including the standard install time of 4. I would have kicked off about that had I thought of it at the time.