NavList:

Thanks for that David. I hadn't tracked the detail (am supposedly getting through 600pp of proofs!) - and, indeed, the remarkable draft of the Sutherland must mean she was towing an underwater array, presumably working on the assumption of potential Russian submarine monitoring.

You're probably also right about the Firth of Forth - though it's not busy in the way the Channel is, where RN ships don't necessarily have their AIS squawking. Equally, given your ability to follow the Sutherland's plot, it's clear that whilst she was obviously engaged in monitoring underwater activity, somehow that didn't count as 'operational' in the 'this is something no one is supposed routinely to know about' sense. So maybe more likely it was a 'buddy' thing - if the QE was squawking as required by the rules, then her accompanying vessel has to squawk too so that navigaors following the AIS plot can see that the two vessels are working together?

I was wrong about the red ensign. Apparently future RN ships during acceptance trials are these days deemed government vessels, not the property of their builders (though there's an interesting nitpicker's  question about the legal status of the Aircract Carrier Alliance) so wear an undefaced (i.e. plain) blue ensign.

Stephen D