Well, the seller signed for the machine at lunchtime last Friday, but I haven't had my refund. I contacted him yesterday but have had no reply, so I have escalated the claim with Paypal.
I was concerned that the seller, having possession of the machine and the money, was trying to delay things until next Monday, when the Paypal case would be closed and could not be re-opened.
I don't think there is much question about what Paypal will do - they have a record of him offering me a full refund, and I have proof via Hermes that he has received the machine. I just hope they don't take the 30 days that they say is typical!