[Arran]

Yes, I believe Kirk does sell those, however I don't know if he is currently producing them or if he has any left in stock. I don't want to kill his business if he is but I believe that he made his molds using a grill from a certain post war model, with an identical grill, that used a more stable plastic. One word of caution though, the grills on those post war sets only came in white, so you can't really use one as a replacement on most of the pre war sets which came with marbled brown grills. You could try casting your own using one to make a mold, or find a more high tech method such as a C.A.M machine, or a 3D printer by scanning an original, but buying one from Kirk is probably cheaper and less hassle.
Regards
Arran