A1 Models in Doncaster used to have them.

Olivia's Trains commissioned their own design of the Class 44 grilles that were unique to D9 & D10.

You may want to email them for further information.

 

Many thanks Smudge for this. I've found the A1 site on e-bay and will be buying various grilles from 'em today. I found an article on RmWeb from "andyman 7" but this was more related to D8 in its restored condition. Stlll looking for detailing articles, but they are few and far between. Was going to covert one end of D10 to the headcode box version but decided it was a bit beyond my skillset! Happy modelling!