Ok one more detail

Bought a new light too
When I went to wire it discovered the wiring for the old one was diabolical so sorted that at the same time
Minor hiccup with the bath.. the chrome waste goes under the floor at a weird angle and hadn’t seated into the underfloor pipe so we had a leak.
Luckily I had the foresight to build in a hatch so was easy enough to change for a better part and now all sorted. Slight mark on ceiling below. A pain but actually I take the view all good as we ended up with a better solution.