Hi.
We loaned a lovely 11.2hh welsh mare in sept for dd 6 as her first ridden pony. she was ok to start off with and very green, but she showed potential.
the only warning sign was that she did rear once at pony club games rally, but that was due to me bashing cups together (in front of her face)
to get her used to the noise as she was a little frightened, and although i thought it was very naughty i gave her the benefit of the doubt and blamed myself for scaring her. (her owner told me she had never done this before)
She does rear when I bath her or if we try to clip her, and its her way of protesting and being a bloody stroppy mare, but she has never done it since under saddle and my dd has learned to ride beuatifully so everything was going well............
at a PC rally on wednesday, again she went well in the morning, then in the afternoon, i was stroking her and pulled a bit of mane out of the brow band and she reared up full height 
twice
I got my dd off and investigated and she kept doing it everytime i touched her ears so I took off her bridle, and took her home 
dd and I were really upset as I realised then, she would have to be sent back to her owner, as i could not risk dds safety ever again on this pony.
I rang her owner and told her over the phone that I dont want the pony anymore. the owner came to look at her and claimed one of her ears was slightly swollen and sure enough every time we went near them, she reared again.
she also mentioned that she once reared with her when she rode her a number of years ago, but had not done it since 
Anyhow, i told her we would keep the pony on grass here over the summer, as I did want her to go back to the allotment where she came from over summer as I felt she should at least have a nice summer here.
This is my dilemma, the owner has been back today to see her whilst we where out, and has texted tonight to ask us to get the vet out for her as she is still sore and rearing when you touch her
My loan agreement says that i need to give 30 days notice of termination and that i am liable for any vet treatment whilst under my care...it also stated that I must have insurance for the pony which to be honest I have never gotten around to doing yet, which I know is stupid.
This is now where I would like your advice.
I have told her I will arrange a vet this week to see to her (which I will pay for) but that I have given her my 30 days termination and that she is welcome to keep the pony here on a free grass livery basis, but she must take out insurance in case she gets hurt or kicks one of my other horses etc...
Do you think I am being fair?
Do you think I have a genuine reason for terminating the agreement with imediate effect due to the pony being dangerous, and should I just ask her to remove the pony asap to prevent further issues?
Thanks in advance for your hel