Hi thanks for all this it's made me think differently about the problem.
I'm fairly sure the message is coming from the Humax. The format looks the same as the one O get at the top of the screen when it connects after switch on. (My Humax is connecting by wifi to my router.)
What I think may be happening is that because the wifi connection to the router is sound but the router connection to the internet is down I get a different sort of message (ie centre of screen etc). I haven't had a chance to experiment but I think if I stop the wifi connection I might loose the message.
Best, Tony