I know why the reversing lights were on all the time - the "plunger" in the reversing light wasn't working. You can see why in the photo where a replacement I got from S&S has the plunger tip standing much more proud than the original. I think the original wasn't releasing properly and despite WD40 it didn't improve followed by one of the wires breaking off anyway.
Fitting the replacement one didn't take too long even if it was fiddly and now the reversing lights come on when they are supposed to and only then.
Next I replaced the top hose which was decidedly dodgy (although in time honoured fashion I'll be keeping it as a spare).
With those all done I drove the car with the top down for 20 miles and it was a real treat. The car handles well and is surprisingly quick actually, although there is the occasional hesitation from it which could probably be cured by a check of points gap and timing etc. Thing is though, with only just over a week to the AutoEcosse maybe I should leave well alone and just get some more miles on the car.