I was at a bicycle recycling charity today talking with one of the staff members I've known for several years.
He was telling me that they are scrapping increasing numbers of decent donated bikes because of the cost of repairs, slump in demand and prices people are willing to pay.
An example was a straight and complete steel Marin Pine Mountain that just needed a service, wheels truing, new cables and puncture repair. They were doubtful if the could sell it for £70.
Are you seeing this?
I’d imagine the market for a ‘project’ would be small compared to the market for a road worthy bike?
My local bike recycle shop went because it was costing too much to put their product on the shop floor. Like your example, they would put new cables etc on a bike that someone had ‘donated’ (thrown away) and try to sell at a price that did not reflect the perceived value. Its replacement, a commercial venture, would do only what was needed to make a bike road worthy, clean it up and sell at an attractive price.
If you PM me with the name of your charity shop scrapping bikes, there might be an opportunity for them to make more than scrap value.
Edit- Ah. Somerset. Too far to be worthwhile :-(