The buyer is London-based which is also good news. Fingers crossed there are no complications!
Update Friday 12.20 - all sorted, smoothest ebay transaction I've ever had, and new owner has ridden off into the sunset (well, noon light drizzle) and appears to be happy. Insurance is cancelled and I get a £3.46 refund on the balance (policy was paid quarterly and expires in a few days), just need to go bank the money and send off the vehicle registration.
update Friday evening - insurers phoned back, refund is actually going to be £46 for some reason.