Well this weekend is going to be some prep work on the Van.
She is due her MOT the end of the month, and I have an event to take her to in December.
So I think top up oil, check water levels and anti freeze, top-up tyres, give the interior a bit of a dusting and then possibly take her around the block just to give things a quick run.
Going to be ordering a 300w 12v heater for the van next week, I'll have to let you guys know how effective it is as I imagine most campers could benefit from it. Essentially means heat on turning the key on chilly mornings without needing to wait for the engine to warm up. Though no good without the engine as would use up the standard battery in under 30 minutes if my calculations are not far off.
We had a 13v heater - may have only been 150/200w, but to be honest it was like someone blowing through a straw - not paritcularly effective unfortunately

Yeah, I have tried those 150w ones and they are indeed hopeless.
This 300w one is the most powerful 12v based one you can buy, so fingers crossed it does the job in the back of the van.
Otherwise I could go down the route of a ~1000w inverter and then run a mains 240v heater. Though need to bare in mind that the standard alternator is only rated for I believe 40A continuous which is just shy of 500w.