Thank you all for your tips
I had my first winter trip away of Queens Birthday weekend and was really surprised that it wasnt as cold as I expected it to be.
I filled the cavity between the inner linning and outer shell with pink batts. Cheap and easy - but a horrible job.
I think running a curtain wire just below the windows and tucking thermal linned curtains in to create an air pocket without the curtains not touching the windows helped heaps.
Just having the right clothing, foot wear and bedding for the conditions made it a lot more comfortable too .
A diesel heater would be a luxury but the cost is really not warrented in a wee weekend van like mine tho.
One detail I should of paid more attention to tho was the lack of traction the van seems to have at the best of times - let alone in the wet muddly winter conditions. Lead to a bit of an adventure involving a friendly farmer pulling me up the hill with his tractor
- ho well just adds to the aventure.