Finally, I took the battery cover off for the first time. It's a thin sheet of aluminium, with little in the way of sealing.
I tidied up the wiring. Someone had fitted a Cetec battery charger umbilical, but this needed a grommet. I also fitted a neoprene flap along the bottom edge (just visible) to dissuade water from splashing up.

Finally I added a square of neoprene kneeling mat to the inside of the cover, to seal & insulate......

And polished the outside of the cover........

This is how it looks with the ply cover replaced and having had two coats of Danish Oil applied.

That took longer than expected (it always does), so now I must apply myself to the demands of MrsW for a while. There is a list of jobs to attend to..........