Having seen the same builder bury and then rediscover the same asbestos on a job once I'm not a believer in it...... Plasterboard is about £170/t to dispose of, with good planning keeping it day it's cheap enough
Had a quick look at it. Quite a lot of salvagable timber, tiles are decent etc.
I have a good friend down the road from the job who has a 3cx and a telehandler. I've got all the small tools and a selector grab on my Bobcat, plus the skills to handle the paper work. Sounds like a joint venture is the way forward.
It's on it's own plot, plenty of room to work. Couldn't be better really, plus the customer wants a bit of tree and scrub clearance done too.