to be fair, a home buyers report is a bit of a joke, Lv 1 and 2 are a joke and you pay a guy to walk around and spot items you can see anyway ( oh look ,its a old roof, it might need replacing, oh look, old soffits, it may contain asbestos, oh look, you have artex, also might contain asbestos, oh look a crack in the wall, might be movement ) they will not move anything to investigate issues
the Lv 3 is ore in depth and should show up issues, often dont and are often fairly if they can see it, so should you be able to
he does sound like he wants to play hard ball though, so test the water with a cheeky bid, he will come up a little, feel he has " got one over on you " and you will both be happy