How wonderful to be able to provide this. I would tick the accessible box under amenities. This would enable people to filter somewhat. Then, if you specify it additionally in your description of the space, it will become clear for people exactly how the space is accessible (ie, for w/c access).
On top of that, may I suggest you put this same question forward under the"host voice" section of this community site. As I understand it (and I am new too, but have been reading quite a bit), that is the space to directly communicate new ideas to the company. If enough people respond/thumbs up the idea (20, I believe), then the idea will be reviewed by the company.
Good luck!