[Larry]

I think the attached might help though sometimes there was a delay in carrying out orders.

Regarding a yellow ring to the wing roundels - these would have been applied pre-war to the fabric winged Hurricanes in the first batch (L1547 to L2146) and what you see in the photo is likely to be the original roundel outer yellow colour showing up at the angle the photo was taken - though I doubt any yellow was actually visible.

As for Codes these should be grey - which the book detailed below says was Air Ministry Grey 33B/157 though I do agree that some Fighters in France and in BoB do look as if they have white codes!

This page came from Camouflage & Markings No2 - The Battle for Britain May to December 1940 by Paul Lucas - Published in July 2000 by Scale Aircraft Monographs.