...I got one but have done nothing with it...It is a bit crude, especially the funnels...and I previousy got some sets of 6-inch twin turrets which are sold separately and not bad, with a view to using them to upgrade the Airfix Nelson... (the) Sydney conversion parts came complete with an Airfix Ajax, and are in (my) attic...
...I think the chap who sold it (calls himself "leroyfox" on ebay) ...I definitely got the 6-inch twin turrets from (this guy)...but I don't recall whether it was OzMods who made it. It might have been as they also did a 1/600 Daring which looks rather like a copy of the Airfix kit!!...He advertises it from time to time on ebay...If you do not know about it, I will send you the reference next time he advertises it...I (am recovering from an) operation last Thursday (12 Feb), and my movements are (a) bit restricted at the moment, so I can't get into the attic to look at the kit...I'll let you know when I get to the kit...
Thank You, Billy - and I know OzMods does (or did, at least) make a 1/600 Daring kit (in resin, IIRC). At their website (the above link), I could not find either this, the Sydney conversion set nor the separate, RN twin-6" turrets - however their HTML plays hell with my older browser (and gets worse every time they "upgrade" the site), so I can't verify whether they may actually not be listed - perhaps simply OOP - by now.
So, when you can get to your set(s), it would be great to have you confirm exactly where they came from, and send us some pics, buddy.
Meantime, best of luck on your speedy recovery, Billy!