Wow
Yep, the scabby sheep thread was me, and she sounds just like your ewe.
I got the vet who suspected mites. He took skin scrapings but found nothing.
Her black, dry, crusty scabs were around her eyes and inner edge of ear, on her udder and under her belly. Basically they were everywhere where there was no hair cover.
She too was really itchy and miserable.
I found she was worse when I brought her closer to home where there was more midges.
Vet gave her a steroid jab and long acting antibiotics, then I put her back over on the windy, exposed hill. She seems a lot better over there.
I'm going to give her another year to see how she goes now I'm aware of it. I will try and keep her up on the hill whenever possible.
If she doesn't do significantly better next year then she'll have a one way ticket I'm afraid. I'm not prepared to allow her to suffer every year, it's not fair on her.