Returning car- Dealer being evaisve on meeting to complete

Hi,

From England.

Recently bought a car but its not in a good way.

I have asked to return it under 30 day notice and the dealer has said yes but couldn't pay until he has received payment from another sale which

I took the car back but no one was home. I have dropped the car off and put the keys in the letterbox with a video of doing this, taken photos of the car and posting the keys and sent a message confirming the return with a picture of the car. His son also saw me as i was leaving.

I have sent a message saying i will come by later to complete the paperwork (i have the v50). I have sent a message asking for a time but he has yet to reply.

Just looking for advice on what i should do next in order to ensure i get my money back? I have 2 days left of 30 day notice.

Thanks