What you might try is finding an obscure corner in which traces of the original paint hide. Clean it carefully with a plastic scourer and spot of meths or white-spirit and see what happens.
Failing that no-one's going to object to mid-grey or something near "Record Blue".
My old, American-made vice is of similar blue. My Denbigh H4 milling-machine seems originally to have been grey, under a tidying-up shade of light-green I'd given it, and that is what I re-painted it, a bit lighter than Myford Grey. (Just ordinary household gloss.) Drummond lathes were originally maroon, but that was probably unusual. .
I rescued one of those little Record drill-vices from its use in a grit-blaster (sacrilege) – so clean but no paint left. I repaired the broken keep under the moving jaw, and repainted it with primer and something near Record Blue by memory, in spray cans from Halford. It has rewarded me with good and faithful service since!
Working for a Govt. Dept. I noticed the small, clamp-on type Record Vices in our labs were all bright red. By special order perhaps?