HiMB, sorry for delay replying, just got back from a Ten Pin Bowling League Cup match, we won 4:2 and through to Round 5 😊
Ooops! I can't think of any type with a gun tub slap bang in the middle of the bridge. 😲
Otherwise I think yours is a simplified version pretty much based on the US produced ELCO PTB. Probably the 80 foot version, known as ELCO 80 (wonder why 😉). Modified from the original Vosper / British Power Boats designs. More of these were built than any other version and most used in the Pacific.
The USN called these boats PTBs while ever other navy at the time called them MTBs. Also suggesting that your model is based on the US ELCO version.
Here you can find oodles of photos of MTBs, MGBs and PTBs.
https://www.pinterest.de/pin/417145984205535643/
Attached is a photo from this site showing the bridge, foredeck and forward gun tub. I have loads more like this. if you like I'll sort out a bunch and post them here or email them as you wish.
Battlecrafts are good, well detailed. BUT, I was disappointed when I bought a set of 4.7" for my destroyer that nothing moved 😡
Now trying to figure out how to mod them without wrecking them.
The guns in the tubs are Twin Browning 0.5" calibre, 50 CAL (for barrel length =50xCalibre). Means that the barrel length was 50 times the bullet calibre! I.e. 25".
Cheers Doug 😎