Fear not, the saga of our new shower is drawing to a close and soon you won't have to hear more much about it. Hurrah!
Meanwhile, the builder is happy about coming back to sort out any remaining snags I identify including the residue of dust.
Someone mentioned that it was normal for powdered adhesive or grout to be mixed in the bathroom (as opposed to in the yard outside the house) and consequently this would always lead to some powder in the air which would travel within the house and settle.
The implication of this is that I shouldn't worry about the mess made by the clouds of grouting powder which were wafting around at the end of the job and left a film of grout or adhesive powder in some rooms.
I can see why a tiler would prefer the convenience of mixing his powdered grout in the bathroom but is this really considered to be good professional practise?