Love a good history lesson. And this was a good one.
You're both welcome.
I should have added that UK cadet forces continued to use the Enfield No.4 rifle and cordite (or any other form that could be procured) 303 for many years after the regular and reserve forces changed to our version of the FN FAL in 7.62mm. I can well remember school Army Cadet Force range days in the 1960s shooting them, and the BREN light machinegun saw some use in its original 303 calibre in this role too, in addition to 7.62mm conversions for the regulars, 'Territorials' (part-timers like American National Guardsmen) and the Royal Marines (who loved their 7.62 BRENs and had to have them taken away almost by force!)