Hi Jo,
There has been a thread that discussed about PAT, link here. The conversation may give you some ideas for your recruitment process? Alternatively, I have tagged @pat-hunt and @debi-mckeown as I know they have PAT at their Trusts, so they might be able to help with your questions :).

Hi Jo, I have been on leave for two weeks and first week back, hence the delayed response to your question.

PAT – Pets as Therapy? The owners of the dogs have to go through the same checks as all our other volunteers. We do have an agreement with PAT where we established who is responsible for what and rules as to what can or cannot occur on our premises. Hope this helps.