Are you interested in keeping the bike or are you happy to get rid?
As you were looking at a trade in, I assume the latter.
If so, I'd let them take it away, chase them up for the result of the inspection and their offer if, as expected, it's a write off.
You seem to have a pretty realistic idea of value so you're in a good position to judge if their offer is fair or not. If it is, accept it, cash the cheque and go shopping.
