What a horrible situation to be in. I've been in a similar one where I recently bought a horse, had it vetted etc. Got him home to discover he's an habitual rearer The owners didn't disclose this, even after being asked numerous times if he had any behavioural issues I should be aware of.

I can't understand why the vet is saying it will cost £600 for the bloods to be tested. Were they taken at the time of vetting? All they need to do is check the bloods for drugs, surely that can't cost that much I would definately take the matter further.