Nice; 2kW of heating for 7p/hour 
The socket for our washing machine and dishwasher stopped working a few weeks ago.Not an unqualified success. After a couple of hours I realised the plug on the secondary extension lead I was using to get the power all the way into the living room was overheating and the fuse would probably have blown if I'd left it any longer. The basic concept is sound, but that extra extension lead is not good. The actual VtL adaptor and the heater plug into the other end of the problem adaptor were both fine though. Some warming on the latter but nothing to get alarmed about.
I'll remove the problem plug and fit a new, heavier-duty one and give it a shot while monitoring the situation more closely.