All white.....

.....on the night!
I put a coat of Dulux Weathershield undercoat over the grey primer. Using a mini roller was certainly the right method, much more even cover than a brush - and a lot faster and less tiring. Tomorrow will be a repeat with the first coat of the finish.
After that I think I have to take the boat out, turn her upside down and bring her back in to fit the bilge rubbers and skeg, followed by more sanding and painting to get the outside painted.