Ash Congratulations on buying a great piece of British gunmaking .

I have had a good look through Don Masters wonderful book.The House of Churchill.

You gun was made in the tail end of 1939.

The Crown retailed at that time for 35 pound Stirling.
The crown underneath is a Baronet's crown. They did make a second grade sidelock with an Imperial crown .
The crown was discontinued not long after yours was built ,and reintroduced in the 60s.
Sorry to burst your bubble but the Crown is not at the top of the list but at the other end of the scale.
It is not listed in the 1922 catalogue.
The legdend is a furphy.

There is quite a bit of space in this book dedicated to the development of the XXV.
Now that you own a Churchill I would recommend buying this book.

sbs470