Drylining advice

Evening,
Need to dryline a *very* small bathroom in a Victorian house. Space is at a premium.
Solid double thickness exterior wall.
Ground floor bathroom.
I don't have space for insulated plasterboard.
Any ideas on what I need to do?
Have already ruled out D&D.....unless someone wants to convince me otherwise!
Cheers.

why have you ruled out D&D? in which case your only other option is to batten it/firrings. But D&D probably easier.

The vibe seems to be that D&D on a ground floor solid wall is a no no.