Explanation of the wording:
HURRAH FOR THE C.R.E. is the traditional song of the Royal Engineers and the Canadian Military Engineers, and is sung or played by the band at all social functions, mess dinners etc.
On the return from the South African War to the Carragh, the song was sung by an RE Company under the command of Major Dobbie (later Major-General), the heroic defender of Malta in the second world war.
When the band strikes up, all present form a long chain with hands on the shoulders of those in front. The chain winds around the room singing lustily. The closing AH, AH, AH starts from a fairly high note and gradually descends. At each AH the chain sinks down a little until all the singers are resting on their heels. When down on their heels  there is a dead silence, and then a whispered SHUUSH. A second silence follows - and then a loud shout of WHOOW! Everyone comes up with a jump.
Mr Stevens was a civilian attached to the Royal Engineers.
Windy Notchy Knight was the nickname for a lanky and knobby-kneed member of the Corps.
Upnor Hard was the bridging site at the RSME, Chatham, England.
Laffan's Plain at Aldershot was a very muddy plain, levelled off by the Engineers over a period of years to earn their special rates of pay. The work was planned and carried on under Colonel HD Laffen, RE.
OSHTA, IKONA MALEE PICANINNY SKOFF MANINGA SABENZA is the Matabele way of saying I AM FED UP AND GLAD TO BE LEAVING. The Matabele Tribe did a lot of labouring for the Royal Engineers in South Africa.

Hurrah for the CRE

See https://cmea-agmc.ca/customs-and-traditions-canadian-military-engineers

Hurrah for the CRE

CMEA-AGMC