The motto scroll with the name is not technically part of the device, and should not appear within the stars. I'm not familiar with the Irish Cunningham arms, but in the group I do heraldry for, there need to be two clear differences between any new proposed arms and already-registered arms.

The Shakefork within the cross of mullets is fine, but the tertiary charge of the silver fern leaf is problematic, as it lies partially on the silver field. One of the earliest rules one learns in heraldry is not to put a metal on a metal, for reasons of contrast. Putting the same metal on metal is right out.

You might consider putting the fern leaf entirely on the shakefork.
Excellent, thanks Mac.

I'm not proposing it (as yet) but it is something to play with and get correct anyway, and advice such as yours, and MOR's would be appreciated.