Which is a more accuraate rifle? The No1 MK 3 or the No 4 MK1

[Homer]

I'm not sure I'm following. Is it an L in the proof in question? If so doesn't that make it lithgow. You'll find this same proof on lithgow actions but with slightly different font ranging over 20 years up to 1941. What Australian proof from the same period are you comparing that has a different font L? Is it the rifle with 1927 dated barrel in your photo's? That would be understandable given the many years between actions.

The crown is present on late lithgow production as far as I'm aware. Perhaps you mean the royal cypher is not.

These are 1940 and 41 lithgow actions. The style of the L looks very much to be the same as the OP's rifle to me.