I’d be worried about them having the majority of space outside, as if it’s on concrete i would imagine the concrete would stay pretty cold as there would be no direct sunlight to warm it up it would just be cold stone, and if it’s on grass then when it’s wet they could catch a cold etc. as they are so small and guineas shouldn’t really be allowed on wet grass, and the uk isn’t known for being the dryest place on earth haha.
I personally wouldn’t get a hutch with an outside space as big as that. I think a big indoor hutch area is more important. But again thats just my personal opinion it’s a nice hutch though, my friend has something similar for her bunny.