In reply to mountain.martin:
Cool - looking at floorplans, it did occur to me that there will be a decent amount of space lost because they're circular, but the missus thinks they are pretty, which is the main thing
I think what appeals to me most is the stability of them in high winds, which is a problem we have at the moment with our current big, but more modern tent. I have some slight concerns about the size/weight of bell tents, but as it's for car-camping, that's not so much of an issue.
Out of interest, do you know what brand the ones are that you rent out? What do you think of the build quality?