Hi Dan San,
Thanks for your prompt answer to my question. Checking the serial numbers of the photos I posted to the production batches in The SE5 file I notice they're all from the Vicker's factory.
Machines from the Royal Aircaft Factory have stripes the full length of the rudder.
c9051.jpg
As does this one straight off the Austin factory production line.
Strange it's never picked up by profile artists and decal manufacturers.