After many many vids watched and reviews read on ND filters I opted for the new Version 2 ND and polarising filter set from SkyReat.
As a newbie I wanted strike the right balance between quality and price. At £69 they’re half the price of the PolarPro equivalent and by all accounts perform just well. There are cheaper versions again but I felt these were spot on!
They’re ND4 to 16. No doubt a 32 (poss 64 too!) will be added at a later date.
As it happens I’m replying to this post having received these as a birthday prezzie this morning from my kids 
!
They fit with the gimble cover on and do not affect the gimble at all. (according to the reviews! Not tried them yet Lazy birthday morning for me lol)