(for me anyway!) When looking for bit cream I saw some of those foot warmers for sale in Boots (the chemical self heating ones like the ones you can put on your back)
Occurred to me that although uneco friendly, they would be just the ticket instead of a hot water bottle at night. So, I'll give it a go this weekend and report back.
Also bought some wasp repellent spray which then leaked all over my bag on the way home. grrr.