Nepaul (Nepalese enigma II)

[gurkharifles]

Sometime ago - the subject of brass buttons bearing "Nepaul" over crossed Kukris came up for discussion - opinions seemed to vary as to whether they were connected to "The Nepal Escort" or alternatively may have belonged to the Royal Nepal Army. I've just acquired these buttons which will either help or further confuse!
1) Nepaul - 23mm - this is one shown before although this one has the makers name - Mappin and Webb London - which I've never seen on any button or badge before?
2) Nepaul with field gun 23mm - with makers mark "Superior Extra Quality" - a mark I have seen before on Gurkha buttons - but I have no idea as to the unit.
3) Nepaul with field gun 18mm - with makers mark "Extra Rich Colour" - which again is a new one on me
4) And then the most bizarre of all - Victorian Crown Nepaul and made in Austria on the front ( I can only imagine this was a manufacturer's error and probably never worn) 16mm - rear is corroded so can't see what it says.
5) Victorian Crown MOHAMED JSHAK ALLAH WALLAH - with makers mark MADE IN AUSTRIA on the rear. 17mm
Any thoughts ? Tim