Self-inflating double bed with a slow puncture (Cubbington CV32)

We've tried to find the hole and applied various patches but it still goes down slowly overnight - we have lost patience. If anyone else has the patience you are very welcome to try! Quite expensive new which is why I am reluctant to just chuck it (never mind the materials etc. going to landfill). Plugs in to the mains to inflate/deflate, but can also be let down quickly by removing the bung. Instruction leaflet, bag and cover included. Can be used as a guest bed at home, but also extra comfort when camping (as long as you have access to electricity).