Thanks All,
I'm really embarrassed to not have spotted something as common as footrot now

.
She's had issues with shelly hoof for about three months (which I did trim back to open up the pocket). Her toes also weren't great, and looked a bit raw. However, this was recovering, and three days ago she was still running around.
I think the footrot must be a new infection which has under-run the previous healing from the shelly hoof - last night I had just thought it was the original condition getting worse. I didn't notice any smell last night either, though I didn't specifically sniff for it! (I take it the smell is the same as with scald?).
So, the plan is to bring her in later, footbath her with goldenhoof+ and give her a jab of alamycin. I'll then trim off any dead bits once everything has dried up, and will then no doubt be back for more advice. Wish me luck!!
