In reply to Stuart S: Cheers all for the replies.
I've been in the quarry at Cambus O'May recently, trying to clean up a few of the lines. The bolts are all still fine, but most of the lower-offs (certainly on the West (left) wall and the easier routes on the right wall) could do with sorting out. The effort has been made to put in 2-bolt belays but they consist of one bolt with a hanger, connected to a second bolt with a chain over the stud and a (non-stainless, rusted) shackle (or sometimes no chain and no second hanger. It means most of the lower-offs are almost single bolt, with no way to back up on the second one. It also means people are leaving biners which is a bit messy and when they corrode they just fill up the hanger.
The bolts are good, and if you're going to have 2-bolt belays then I thought it would make sense to put on some hangers with a stainless ring or stainless maillon. At least then you'd have 2 clip-able bolts and they'll still be in good condition in 20 years.
I'm happy to do the work, and will probably replace as many as I can afford if people think it's a good idea but it might be nice to do as many as possible. You don't know if Tim has a stock of 10mm hangers with rings or stainless maillons I could buy?
As an aside, the routes there, although all manufactured, are really good. It's dried out nicely and would be great to see some people in the quarry.
Sorry for the rather long post, any ideas would be welcome. cheers!