Unidentified Nepalese Coin

Any help identifying this Nepalese silver coin? Have checked all the Krause catalogues from 17th century on and can't see anything like it, although it is obviously Nepalese, Measures 38mm wide and weighs approx 21.4 gram, which would make it, in terms of weight, approx 3 mohars in face value. Has plain rim.

The piece has mount marks at 11 o'clock and 1 o'clock, which leads me to suspect it may possibly not be a coin, but instead a medal which has had its mount removed (possibly a miitary medal)? alternatively it is a coin that has been mounted for wearing as a medal.

Any advice much appreciated.

Pete