Yea I'm getting one of those

simple, not sure where to house it yet though, doyou have a pic of how you've done it?
Mine's not actually quite the same as that, it's on a round wind up cable storage reel and it only has 2 sockets but it's enough for me. I just store it away most of the time as I hardly ever go on sites, so it's only really used a couple of times a year or when at home and working in the van, or for battery charging etc, so when I use it it's just loose in the van, and then packed away and tidied up when moving. You just need to make sure that you remember to unplug it before driving off! On sites I only really use it for powering an electric light, the laptop and a low wattage elec heater (have a look in Poundstretcher etc as they often sell them off cheap this time of year, mine is a lightweight halogen heater with 2 bars, each bar is 400 watt, so the box said 400 - 800 watts, it cost me a fiver from poundstretcher in their spring sale last year). You want to avoid anything that uses much more elec (higher wattage) than that if possible in case it trips the electric. Other people can probably advise you better than me on electric consumption and what you can and can't use on elec hook up.
The cable goes through the seal at the bottom of where the back doors meet at the bottom, I didn't actually have to cut a notch in rubber door seal cos there's plenty of space (and a howling draught) at the bottom of my doors but if your doors are a tight fit you might need to. Only a tiny notch should do.
It's definitely worth not ruling out things at this stage as you'll probably find that you get hooked on using the van and will want to use it even in the crappy english weather, if only just to get away from the family for a night or 2, or to use as somewhere to stay after a night out to save having to get a taxi home etc. And like I'm finding now, it's a pain in the backside having to unload the van in order to do more work on it, to add more luxuries etc. I didn't want a sink either at first but even though I'm not (at the moment) planning to plumb in a tap, I have now decided to put in a sink (I picked up a secondhand one for a tenner through this forum) as being able to wash pots etc inside in bad weather or at night time will be much easier and also it means I'll have somewhere to put dirty pots etc if I don't get a chance to wash up before moving on. I'll fix my drainage pipe to the sink so that I can at least just rinse a mug inside the van in the sink. I just need to design and build a unit for the sink now.
For my bed, I've been using a sunlounger, £15 from Poundstretcher, but it got too saggy and so I got some 11mm ply and made 3 boards, hinged so that they fold away to use on top of it. Then I found that the mattress (memory foam mattress, again in the spring sale from Poundstretcher £20) was damp in the morning so I've drilled ventilation holes in the boards which has made a big difference. The bed was lengthways in the van but when it was down there was hardly any room to move so I'm about to try to figure out a way of having it width ways over the top of the wheel arches, but the sunlounger is about an inch too long so I'm trying to figure that problem out at the moment, it's a bit like doing a jigsaw puzzle.
I use a Ghillie Kettle (also known as a Storm Kettle or Kelly Kettle) which is one of the best bits of kit I've ever bought. It's a bit bulky but it works best in windy weather and costs nothing to run as you just use twigs, leaves etc. I always carry a bag of dry kindling with me though so that it's easy to light, but you can usually pick up bags of kindling from garages etc. You can also burn any paper rubbish on it. Once it's lit and burning well, it will boil a litre of water in a couple of minutes, and leaves no evidence on the ground. You can even use it as a mini bbq if you get a metal trivet to sit on the top of the bottom bit which contains the fire.
Hopefully if we do manage to meet up, you can try the Ghillie Kettle out for yourself and see what else I've done in my van. I've had loads of good ideas just from looking at what other people have done and adapting their ideas to suit my van.