Nominet confirmed domain transfer completion on 2 Feb, Sedo advised same day. "If we don't receive a reply from the buyer within 5 days, we will be able to close the transaction and release your payment." Now passed day 10 and counting, reminder sent to Sedo. Buyer insisted on using Sedo, costing him significantly more than alternatives. I removed £250 discount to accommodate his request, so probably no surprise at his lack of co-operation.