Added 3 clear coats today after a 2 hour search for another litre of acrylic - not much seemed open today.
Happy to say it matches nicely with the back of the guitar.
Ended up with 2 coats of japan black + a run (ah well), sort that later. Seems to have done the trick.
Ended up staining the fret board with one coat of japan black then quickly tested some beeswax polish which darkened it that little bit more.
Should look alright - pics on assembly in a couple of days once it has dried properly.