BFA paint color question

The 1943 ANA coded paints were an attempt made to standardize paints used on Army, Navy, and Lend Lease aircraft for production & logistics purposes. Aircraft slated for Lend Lease such as your Hellcat would have been painted in the  ANA equivalent of the FAA or RAF shade. The Air Force Colors Vol.2 by Dana Bell has a listing of these colors. For an early Hellcat that should be Slate and Dark Sea Grey over Sky. A late Hellcat would be in overall Dark Sea Blue, the same as USN F6Fs. 

I agree on the Grumman Grey cowl, that makes perfect sense. I found some photos of restored F6's and they are all Sky color underneath and in the bays and on the gear. 

The IPMS site mentions some RAF colors but I can't find specifics on this like I can for the US paints.

Currently I am leaning toward Sky on all the underside parts and Grumman grey in the cowl area unless someone else can point me in another direction.

BK

The planes would have been painted in the factory by Grumman to Royal Navy Fleet Air Arm (or FAA) specifications. The inner cowl would most likely be the same as USN, which IIRC off the top of my head was "Grumman Gray". Have a look at the IPMS Stockholm site article on that stuff. And educated guess says the flap and wheel wells would be painted to match the surrou nding area, and on USN aircraft, but like I said, that is strictly an educated guess.