It wasn't a wind up extension lead. The extension lead only had the dishwasher plugged into it, and it was rated for 13A.
The dishwasher's moulded plug melted and fused itself to the socket of the extension lead.
On a side-note, my cub/scouts group were doing a fundraiser when I was a kid and...
Our kitchen has (since we got the house) always had a space for a dishwasher under the worktop next to the sink, but there's no mains power socket nearby, so we were using a 13A extension lead. We recently had a scare of it overheating and [luckily] tripping the circuit breaker, which led us to...