[landroverroy]

I'd be inclined to agree with Foobar as I've had a similar thing on the face of my sheep. (Usually young stock) We aren't over inundated with midges so it never got to the extreme itchy stage but went away of its own accord.
If your potion of teatree oil etc is still working, then I would carry on applying it and wouldn't worry too much unless it gets worse. 

[milliebecks]

Thanks all!
Reapplied the 'potion' today and dosed them all with crovect, which i had planned to do anyway.
It may be wishful thinking, but I think the area round her eyes looked slightly better. She's certainly eating and moving normally with the flock.
I'll keep an eye on it and speak to the vet next week if there's no improvement.

[Anke]

Crovect ? Why?

[Hevxxx99]

It'd help with lice and mites....

[Marches Farmer]

I doubt that's the problem.  Don't forget Crovect has a withdrawal period if you take her to market.