[Big Benny Shep]

Ruggle worked really well on our tups heads, as they were being bothered badly by flies, within mins there were barely any around them. We also use Buzz off buckets which contains garlic, we put these out early May and they seem to help, got some helpful vitamins and minerals in them too

[Hellybee]

Interesting, I've heard of it used for itchy ponies, but not for sheep up til now

[Big Benny Shep]

There are a few options around http://www.caltech-crystalyx.co.uk/products/products-folder/garlyx/
Ive used these before, can't find the ones I'm using now, but I only changed because the shop changed hands and supplier. 
They don't seem to eat them as fast as they eat mineral buckets in winter.