I guess I'm lost then Effy. You say it's "unacceptable" and the solutions to have it fixed aren't good enough for you. But then you say you're not saying for him to get a new motorhome. What exactly do you want then? He has three choices. Leave the hole there and ignore. Have the dealer fix it to his satisfaction and then take the motorhome. Or don't accept the motorhome and order another one. If it were me, I'd tell them to fix it and take the motorhome.
As for your house, I'm in my 4th house that I bought brand new. I can assure you every single one of my houses had a punch list of items that had to be repaired once I took possession. And most of those items we didn't see for several days or even weeks. So sometimes things don't stick out. The OP's motorhome has full body paint and the hole was 7' off the ground. The OP doesn't tell us how the hole was found, whether he found it of if the dealer found it. Sounds to me like it's lucky it was found.
