Eco-tourer- Bed

Hi all,
Just returned from our first trip in our tourer, Melbourne to wollongong via the hume hwy then south back to melbourne over two weeks. The tourer preformed better than expected , only issue l have is the bed! Being an offroader with shower n toilet so the bed is a tight double. is has a inner spring mattress of good quality and is comfy to lay on but we cant keep to sheet and blankets in place. With the bed being confined between walls the doona cant hang over the edge so it doubles up and then you get cooked, Have tried blankets with much the same result. When we awake in the morning the bed looks like a war zone, l'd like to say its caused by our love life but who am l kidding. In the 2 weeks away l had 2 good nights sleep fitted sheets that could be tied underneath to take up the slack would be good but think the blanket could be another issue. Has anyone else had these problem or someone got some ideas how l can get some more sleep other wise am contemplating selling the van
Regards red eye Theo