Thank you for all your suggestions.
I'm not sure I'll get anywhere with police. My friends teenage daughter was assaulted by 2 boys a few weeks ago and police have done F all. They haven't even got back to her yet.
I've also heard RSPCA are useless but will give them a go anyway.
OK to answer a few questions.
I was telephoned to say she "thought" she cut her tongue. I went straight over (2 minutes) and found my dog hysterical. She was hyperventilating and blood pouring from her mouth. It wasn't overly hot in there because they had air conditioning.
I lifted her onto the table to see if I could see the damage to her tongue but it was hard to see because there was so much blood. Then I noticed her eye which was swollen and blood shot and said what's happened to her eye and she said she hadn't noticed anything wrong with the eye.
Later I phoned her and asked again and she insisted nothing had happened.
The vet and vet nurse said this injury could not happen from just getting stressed.
She's basically got a black eye. You don't get a black eye from stress. You get it from a blow to the eye.
She's normally very good to be groomed. A bit anxious but nothing untoward. She never bites or anything. I can't understand what on earth could have happened.
This is a new groomer (3rd time there). My dog went to my previous groomer for 6 years with no issues. He always said how good she was. Old groomer sadly moved away so started going to this lady who was recommended.
She works from home and works alone.
However I noticed her partner was there yesterday but he said he was just helping clear up all the blood. She did however have another dog there (even though she told me she only does one dog at a time). So I'm wondering if the partner was helping and did it. Either way it's her responsibility though.
I think initially I'm going to ask for cctv (which I doubt will be forthcoming). Plus a written report from the vet and a written report from the groomer. Then I'll go from there.
Will also look into legal advice.
Any other suggestions greatly appreciated.