WW2 Royal Navy cap tallies

[Lemataf]

Hello,

Attached an interesting picture taken first half of 1940 (inscription on the back indicates «*Jan 1940*», if exact datation, was then based in a warm location), on anti-submarine trawler HMS Kelt.

This snapshot offers a nice sampling of worn cap tallies, at a time when anonymized ones (HMS, ...) should have been worn (I tend to understand). From left to right, one can read: «*...lution*» (HMS Resolution?), likely from bearer previous assignment, then «*... Reserve*», then no cap tally at all, it seems.

This triggers me a few questions then:
1- After the outbreak of the war, when exactly was the requirement for all RN seamen to use only anonymized cap tallies (HMS generic ones) introduced?

2- What could be the full cap tally label for the one ending by «*... Reserve*»?

3- During ww2 time period, did the RN regulation allow to wear a cap w/o any cap tally? If yes, in what specific circumstances?

Thank you for shedding some light on this & all the best,

Jean-Daniel