What temperature does your paint freeze at?
Linseed oil freezes at around -20C so i'll be fine!
Thanks for everyones advice and tips, and for those sticking up for me in favour of the adventure.
The only thing putting me off taking others is that everyone I know who I could convince to come with me are much less experienced than me, and I would be willing to bet it would actually be less safe going in a group, since I would be spending most my time babysitting them.
There are definitely better places to hot tent but unfortunately none of them are as accessible by public transport than Edinburgh, except perhaps the forests around Loch Tummel.
I have done a bit of research into fires. It seems open fire in the forest are (quite sensibly) not allowed since it is peat soil, but things can get hazy when it is a raised contained fire, as mine will be. Obviously a plume of smokes the same either way though and will be checked out regardless. It seems Abernathy forest is slightly more accommodating than Glenmore though.