Hi Ozsat and apologies for the slow response.
Yes have been rebooting like mad. I think I've tried all sorts of connection/reboot options but as time goes on in a less structured way.
I think we can definitely say the V6 is fundamentally working, is fully updated and seems be very responsive. And it works a treat on HD sets ... the Pana CS600 is fine and the even older Pana DT30's are fine, is just the EX700B (4k) set new out the blocks this year.
That said, maybe there is a setting that lends itself better (on the V6) to working with the EX700B
Here is how the V6 is set right now ....
There are no special settings optioned on the TV .... this is the CS600 set, the oilder one. Here is the new EX700B...
And side by side ... same V6 box, cables etc etc ... when I connect the same O/P from the V6 we just get blank screen with the HDMI1 channel shown in the corner.

And then reconnected to the older HD set.