We got
this one from a small local firm, York Timber Products. I bought it 5 or more years ago, for my hobbies but have now cleared it for bunnies. The window opens so doesn't need removing, just a fly screen fixed on the inside, to make it secure so we can then leave it open when buns are in.
My husband is doing that today. Then my birthday in a couple of weeks so my present is going to be a Runaround door and tunnel, which are going in the back wall of the shed, as that faces the garden.... and we have already got the materials to build a new run. We are moving the bunnies' big double hutch in there, but one bun may well be free range on the shed, as we know it is mouse/rat proof (unlike my outhouse which I never quite trusted to be rat free, despite plastering up all the holes in the walls, etc). We live by a river so lots of water rats in the gardens.
Bunnies will hopefully be moving in later today or tomorrow. We started stripping paint off the side (stupidly painted it rather than used wood preservative) and so the one side we started to strip has to be finished and wood stained today. I will do the rest in spring.