Anna Kettle wrote:
I have allocated a space for a shower-loo-sink room but what I'd
_really_ like is to squeeze a separate loo-sink into the space as
well. After lots of entertainment as I drew the layout on a large
sheet of white paper and walked around to make sure that there is
enough space to fit it all in, the answer is yes it will fit ...

Mock it up with a stool/boxes, to see if you can actually physically get
round the area.

... if I make the wall between the shower-loo-sink and the loo-sink
out of something much thinner than a normal stud wall. I'm thinking of
using 22mm blockboard faced with 9mm plasterboard on one side and
faced with a wall of the shower on the other side.

I'm planning for the shower to be "Steam cabin" Screwfix 83798 so the
shower wall will be a sheet of plastic

IMO, this will be fine.
It will be marginally noisier, and slightly colder in use than a
'proper' wall, but...