First use of Pip Squeak and Wilfred for medals?

[WW1Daily]

Given that the eponymous Daily Mirror cartoon strip first appeared in 1919 I would assume the informal use of "Pip, Squeak and Wilfred" for medals would not have been long after -- but does anyone have any records of very early use to denote use of the phrase for the British War Medal, the British Victory Medal and either the 1914 Star or the 1914-15 Star?

Or come to that, the earliest use of the phrase "Mutt and Jeff" for the British War Medal and the Victory Medal alone?

My guess would be that both terms began colloquially among collectors -- or possibly at remembrance events but does anyone have any record, suggestions or guesses as to first usage?

Were there any books or medal collectors magazines or newsletters at this period that might have mentioned them fo example. Or any particularly notable wits among medal collectors or dealers?

At the moment I believe the earliest recorded usage is a slang dictionary of 1938 so details or suggestions for any earlier references would be much appreciated.

Best wishes

Paige

[Philip Wilson]

Pip, Squeak and Wilfred was a long-running British newspaper strip cartoon published in the Daily Mirror from 1919 to 1956,as well as the Sunday Pictorial.

'The 1914-15 trio were sarcastically nicknamed Pip, Squeak and Wilfred after these three cartoon characters, by those who thought them unworthy of the service they represented'- see page 17 British Campaign Medals of the First World War by Peter DUCKERS.