In message , "Brian Gaff (Sofa)"
writes
Half the time it means nothing as few respect that flag.
I have noticed that NHS addresses are very intermittent both ways no matter
what email client I use, one in particular for my doctor has the same issue
whether I use my isp email or gmail.
Very peculiar.

I have looked at the message sent times to see if they coincide with
heavy wi-fi use here. My wife has discovered netflix and there are
regular remote school sessions with grandchildren etc.

Nothing jumps out.

--
Tim Lamb