Can anyone ID this button?

[bananamafia]

I know its a long shot. but i've been trying unsuccessfully for a while now to ID regiment of the officer via the button on this photo.
It does have some distinctive features, but i can't seem to match it up with anything.
He was obviously in india at some point as he has the 1936-39 IGSM if that helps???

any guesses/suggestions very welcome!!