I was thinking instead of bringing extra blankets bringing a rabbit fur jacket I got off ebay. (it were only ten quid!!) though I havent worn it I dont know how warm it is. My reluctance to get blankets is because I have such an awful time getting in the hennessey , pushing the army blanket underneath me and on top. it doesnt help that its in three peices since I cut an apron out of it for the viking meet. I could possibly bring a sheepskin coat instead , thats the warmest thing I own and way better than an underblanket.
I'll throw a spare Sleeping bag in the car and it'll be there if you need it