NWF Naval Brigade Artillery.

[Harry Faversham]

Wot about a Gatling Gun?

[FifteensAway]

Afraid all I have are some 25 mm stuff as left overs from the Great Estate Sale that beset us locally earlier this year.  Most likely too small for your needs.  Either Ral Partha or Minifigs.  I figure to -eventually- paint them and sell them.  But the extras I'd let go gratis.

[Plynkes]

If you mean an Indian Army Gatling, I'm not sure they even had them, and am pretty sure nobody sells them. If you are determined to give them one you'll have to find some crew figures who don't look like they're too obviously manning a cannon (or do some converting) and pair them with one from a British Army or Royal Navy set.

Historically speaking (though I realise that isn't really a concern), I believe any Gatlings used on the NWF would have been crewed by the RA, but I'm certainly not any kind of expert. Somebody such as Mad Guru could probably tell you.