and another thing that you may or may not want to do is get a back person out as my friend bought a calm quiet 17 year old ex event horse as a compaion and when she got him he was just as you described and my mum sugested geting the physio out turned out his back and poll were really really bad now he his the nices horse to ride

also we did what your not ment to do which was buy a 123cm pony for me to show when i was like 8 without trying we got her home and she was a brocko but we decided to get hyer back done and she was the most amazing horse ever until her death 24/12/08

so if you cant give the horse back try something else

xxxx

Oh I can strongly agree with that!!!!  Our second horse was a private sale and we paid the same sort of money as you have (a lot less than our first problem horse) She was 16yrs old and she has some minor issues.  You don't pay that little money and get perfection BUT her issues are deal-withable!!!  She doesn't like her back legs being touched and will sometimes lash out and she doesn't like being girthed up but we have solutions for these which don't upset her and keep us safe.  But she is what we paid for and it helps that it was our vet who vetted her!

Whatever you decide to do I wish you the very best of luck.  My instinct (easy to say not easy to do as proved by the fact that I still have my unsuitable mare ) is to sell her on honestly to a more experienced owner and get some help when looking for a replacement so you can be as dispassionate as possible (or your experienced pal can force you to be!!)