Hosed the bathroom by mistake!

and it figures in Alan Aykebourn's "Absurd Person Singular"

I suppose, although the ROI is probably rather low! But I got it to reduce draughts in a wet room with no shower screen.

I took out the 4 " and replaced with a 6" and the idea was to replace the 4" piping with 6" only to find out that where it went in to the loft I had about 2 feet headroom and would have been eating insulation, as for where it exits I dont know. So I got a 4" to 6" pipe adaptor and used that. Even in my younger days I would have struggled with the access.

One way to reduce the noise quite a bit is with a ducted fan rather than a surface mount one. That way the motor noise etc is out of the room.

Was this a special one? They are only £10 to buy new.

I made enquiries in my local hardware shops (the equivalent of B&Q - maybe Smith's DoItAll in those days) and they all said that they didn't stock them and recommended a hire shop. That was in the late 80s or early 90s.

It was a box spanner rather than a flat one, because the amount of spray-on insulation on the cylinder prevented me using a flat one with a slightly cranked end, which is the more common type. I remember it was bloody heavy to carry: there was a lot of steel there!