Noticed over the past few days the 3 y/o ewe does have a nasty patch on her back. We tried putting some bright yellow ointment a few days ago which went black.
I have been told to wash with warm water, dry then apply Crovect.
Update to this post
Organised everything I need to wash, dry and Crovect my ewe. On cleaning the area I noticed the skin was clean but there was no wool.
Clean as much as I dare, dried thoroughly and then applied Crovect just to the area. Will keep an eye on this to see the progress.