well, manager was a bit reluctant to get a vet in before we'd tried ourselves and good news, we got the ring of! Did it a bit like ginling suggested, although i used one of our tiny fine bladed hacksaws, was going to use a stanley knife but using the hacksaw was easier and safe for both chicken and humans! Under the clip looked fine, no redness, cuts, indents etc, she even let me touch it without any complaint. We did bout 7:30am so she was still a little sleepy which helped, by the end of the day she was putting weight on the leg and limping a lot less, so were holding off culling and giving her a chance and are going to be keeping a close eye on her, if she shows no improvement by monday we'll prolly cull, but after seeing her i'm hopeful we wont have to, but we'll see. I think we caught it time, just.
2 more chickens have tags on .. which we'll be getting off next week, hopefully that'll go smoother as they look a little loose still, but there coming off all the same!
I also might do scaly leg treatment on em just to be sure as well, after having a good long look at all their legs the older hens in particular have very white scabby looking legs.