Can the boffin be believed?

For something to do over lunchtimes at work I access the firm’s stock of old reports for an interesting read. So what you may ask? Well as I work at Boscombe Down the reports are that of the RAE and A&AEE and other government reseach establishments that became QinetiQ. A small number of the old reports have been scanned and made into National Archive open documents.
Todays reading was an RAE report from June 1941 reviewing aerodynamic features of interest of German aircraft examined by the RAE.
The following is part of the entry for the Me 109F * and it more or less stopped me in my tracks.
[ATTACH]187787[/ATTACH]
So yellow rings around the German markings, truth or rumour? I’ve never seen it mentioned or pictured before. Just what was this statement based on? pilot reports or salvaged wreakage?
Over to you.

* The report calls it the Me 109F so lets not start the Bf/Me debate.