I purchased this at the Ruahine Antique Arms auction

Both cup & saucer bear an unknown Museum's collection # painted to their base

I have copied the auctioneer's description from their catalogue

Only 1 name came-up on the Auckland War Memorial Museum database with the spelling of Plunket, she was a nurse, the other "Plunkett" were enlisted ranks

I do not know how accurate the spelling in the catalogue was ("Plunket" New Zealand's largest provider of support services for the development, health and wellbeing of children under 5)

However, there is a strong probability that he was IRISH

The man I found in search on the WWW was a TRULY EXCEPTIONAL SOLDIER

https://www.thegazette.co.uk/London/issue/30507/supplement/1600/data.pdf

The Royal Irish Regiment SERVED at Gallipoli

Plunkett was the RSM of The RIR at time of Dardanelles campaign, but by END of WW1, rose to the rank of Acting Colonel

A Sergeant Major at the time, James Frederick Plunkett was awarded the DCM Distinguished Conduct Medal.

The citation read: "For conspicuous good work & repeatedly distinguishing himself under fire"

Apparently, he had a good war & ended up a high-ranking officer (Lt Col or Brigadier). Richard Holmes, in Tommy, mentions him & uses the adjective “legendary”

Plunkett was indeed an outstanding soldier commissioned 2Lt R Irish Fusiliers on 23/5/15 Lt RIR 22/11/15 Capt R Dublin Fus 23/12/17

Already the holder of the DCM & MC he won no less than three DSOs in 1918, together with the Croix de Guerre.

He was twice recommended for the VC

CONSIDERABLE PRAISE of this officer

Pages # 185 & 186 HERE = https://tinyurl.com/J-F-Plunkett

The moustache cup (or mustache cup) is a drinking cup with a semicircular ledge inside

The ledge has a half moon-shaped opening to allow the passage of liquids & serves as a guard to keep moustaches dry

It is generally acknowledged to have been invented in the 1860s by British potter Harvey Adams (born 1835)