USS Buchanan DD131/HMS Campbeltown

I hope your version still has the 131 decals.

The best direction for the kit is to stick with USN. There's a PE set. Bear in mind that lots of plastic has to be removed if you add PE.

Even the Campbelton in RN service has a lot of modification. For the raid itself it was made unrecognizable, and ugly too.

Revell 1/240 got it for my brother in law a few years ago and he has decided to build it.

Flyhawk just released a dedicated Cambelton w Brit mods already in place...unfortunately its 700th scale and too tiny for my tastes..

sharkbait, what scale?

Decks should also be cambered, not flat.   Rebuild with sheet styrene.  But when you do that the deck houses need to be scribed to the arch of the deck.   Perhaps rebuild them too from sheet styrene.  

On the positive side,  there are replacement 4-inch guns available through Shapeways

There's a nice article over on modelwarships.

 The decks should be steel, not wood.

Guns are really poor.