Tough it out mate if you get to cold in the night build a fire and shiver til your warm againMy 1st option is the tarp n hammock.
My 2nd option is the 2 second tent (in camo naturally).
My 3rd option is the car.
And my 4th and very wimpish option is to nip home for a kip each night.
A good tip is to eat some high calorie scran just before you go to sleep stokes up the internal fire and keeps you warm