I once heard of a farmer swearing that the best thing to do with a ewe with mastitis is shoot of the teats with a shotgun !
there you go folks its now in black and white on the forum so it MUST be ok ! 



Yes. Thank you for that super helpful response.
FYI - the ewe in question is absolutely fine now. I told my vet about the udder injection and he said whilst he doesn't do it personally, he has seen farmers getting good results from it. He also advised some Metacam to help her with pain relief.
Susie now has a perfectly normal looking udder. There are no lumps, no lesions, no pink milk, no flakes/strings etc and the udder is now all nice and flaccid again. I've been stripping her twice a day just to be on the safe side, as her lamb has now got into the habit of only nursing from the other side.
So it looks like we caught it in time and she won't lose her quarter
