People may laugh at this option, but it is excellent value and has more comfort benefits...
We have a beach and for convenience our two daughters sleep in the roof (which is a very comfortable bed as standard because of the memory foam and slats, if it wasn't more convenient to have the kids up there we would use it!)
The downstairs bed is approximately kingsize in width but a little shorter, it's perfectly adequate for my wife but I'm 6'4" so my feet hang off the end. in our old van we used a square sleeping bag opened out to lie on and then used our duvet on top. However - even with the sleeping bag it's still uncomfortable.
We were going on holiday at Easter and decided it would be too cold (no diesel heater) and the fan heater we use on hook up is quite loud and disturbing and never quite gets the temperature just right. so we were looking at cheap electric blankets we could use on both beds.
I noticed this:
http://www.argos.co.uk/static/Product/partNumber/4501048.htm
checked the measurements; it's slightly longer than the bed but I just tuck our chiller under my feet and then have a comfortable full length bed again.
Compared to the cost of most of the toppers it is great value and has the added benefit of offering heat when you are on a hook up! Which I can honestly say was amazingly luxurious, without a heater in the van we were all toasty with out heated toppers! They also have zone heating and timers so my wife who sleeps colder than me can turn her side on while mine is off or on low, you can have it hotter at your feet and cooler for your body, and set them to be on all night or for a limited time to go off automatically. Getting into a prewarmed bed felt like we were totally cheating on the camping experience!
In terms of actual comfort it made a huge difference but is still slightly less comfortable than the upstairs bed it did however totally transform the bed for us.
We use a kingsize fitted sheet over the top and a kingsize duvet. When packing away I fold it twice towards the back of the van and it sits neatly and comparatively compactly on the rear shelf with all our bedding wrapped up in it so it is easy to deploy again when we need it next.
If the heating is not required (i.e. south of France in summer!) we just detach the cables and leave them at home.
The topper also comes with a 3 year warranty and a washable fleecy cover...what's not to like!!
W bought the double for our girls in the upstairs bed which is a bit big and therefore goes up the sides slightly but they were also toasty warm in some very cold weather (sub zero outside).
the only difficulty for these is you need two sockets for each topper so we took a four way adaper and plugged them all into that. Current draw for both blankets didn't cause any problems witht he hook up as they only draw about 80 watts each (I think?) and we could run other things at the same time like the electric hob.
phew, sorry that was a long post, apologies.
