Hi @Dermot-and-Debra0
I'm hardly vastly experienced as a host, but I would think so long as you made it REALLY crystal clear in your listing that that was the set up, I cna't see a problem.
Of course come guests dont' read, so i'd be inclined to say it 3 times
once in your listing
once in your house rules
confirm again at booking and say if it's a problem there's still time to cancel.
If people don't like it, they won't book it ( you would hope)
The only query I would have is, is there a potential for a public liability claim here - spilling water when transferring from kitchenette to bathroom and slipping and falling.... hurting back when taking water from bathroom back to kitchenette to fill up the urn... AND I can see people creating a bigger mess that way than just leaving stuff in the sink. Personally I would prefer to be able to clean up after myself rather than having to rely on a host to come and retireive things and return them, but some guests woudl probably love to have you do their dishes. You know your listing best and the types of guests you're getting - your reviews are great, so go with your gut I'd say.
Just my thoughts.
Others may have further insights
Good luck!
Cheers