I've just seen avery intersting picture on another forum
The way this was charged in at least one place:
2 * 13Amp plugs paralleled into a 32Amp Cee-form. Called a widow maker for a very good reason: unplug one and leave the other in and you will get shocked, hard. A very dodgey, dangerous, bodge indeed. Something I reckon will be increasingly used as electric cars come into being before the charging network. I don't know if they're specifically illegal, but I'd hate to be the electrician who did it.