Hi Adri, thanks for your reply.
The TV, hub and TV box are all still in the same original room, I just moved the devices a few feet to a different wall of the same room as I've rearranged furniture. So the white cable is now outstretched from the isolator plate to the TV unit. Everything is plugged in as it should be. The broadband works fine on other devices, but is intermittent on the TV, so streaming channels are sometimes interrupted.
Yes I would like a relocation/extension of th white cable please, so that it's not outstretched across the corner of the room. Please advise how I can get an engineer appt arranged to do this. Many thanks.