niceandclean,
An extension reel that takes say an electric drill should be fine, dont forget to use a safety cut out.
I used Paraffin in 6 heaters in my house for 2 winters, they are ok once you learn how to use them.
Hi Jeff
Thanks for that. I have and outside weatherproof box that is attached to an RCD. I will pop to B&Q and get a new extension cable.
Cheers

You would be better off making your own extension, using artic cable its designed to be left out in the freezing weather ( the ones you buy from wickes and B & Q are not, they are indoors only, the plastic coating freezes and cracks ).
I bought a rubber 13amp plug, rubber double socket and 6 metres of artic cable for £7, it takes 20 minutes to make up,
My van has been lovely and warm in the mornings , also no ice on to scrap off the windowscreen,
Darren