And while I'm on the subject of third party detailing kits and their dual use for both detailing and for replacing breakages, I can also recommend
Master Models, based in Poland but like CMK readily available through UK based Ebay sellers. I'd managed to catch the rear turret guns and break a couple so, these brass ones from Master Models will replace them - you see them here after applying of Birchwood Casey Brass Black, as they arrive in shiny new looking brass:
Still a few spots to blacken, I can now see in that photo!
When I last built Airfix kits of WWII hardware in the 1970s, as far as I know no-one made resin, brass or plastic detailing kits, or if they did it was of course pre-internet so far fewer people would have known about them. I suspect though that it's modern advances in small scale manufacture, 3D printing etc that's allowed for the profusion of such things.
When I re-entered the modelling world in about 2012 with railways, those kits were mainly small manufacturers and they sat alongside railway detailing kits on the same trade stands at shows so I took it for granted that such things were quite usual in railway modelling, but it's only recently I've discovered the enormous amount of military stuff being made. It's only ever going to be an occasional diversion for me - usually a riad vehicle conversion to provide a load for a railway flat wagon - but it's good to know these things are out there.
I also suspect though that the number of military modellers around the world is considerably larger than railway modellers and in fact this stuff is probably being produced in quantities that dwarf the likes of the now sadly defunct Markits, Branchlines, Gibson and the rest...