That particular knife was issued to BOTH members of the Royal Navy as well as the Army, hence the addition of a marlin spike. The Italian navy as well as the USN still issues something of a very similar pattern to their sailors.
Just a few years ago, you could get these in unissed condition still wrapped in wax paper and covered in cosmoline next to nothing. Since those days, the market has pretty much dried up.
As a WW2 reenactor, I remember seeing British and Royal Canadian Army reenactors using these in their personal kits.