So I decided to go for the civilian scheme in the end. Spook Towing sounds like a plan (or a strange pastime).
I made a real mess of the wheelhouse doors and windows painting. Also, despite my most careful efforts not to get glue on the window transparencies, the glue fumes did for them instead, so minging windows as usual, I'm afraid.
I'm just waiting for a dry, wind-free day so that I can spray-varnish the hull, then I can crack on with the deck fittings.
The colour scheme is going to be very much a freestyle approach, although I am using mainly colours that I've seen on other tugs.
It's not coming together as neatly as I had hoped but, with a bit of luck, the finished product should pass muster.
Anyway here are a few update pics.