Thanks for the help, I’ve now done the connection checks & played something on demand on the 3x V6 boxes & they are working good. When I went to do the connection check the same way on the old TiVo box the facility isn’t there but it says connection is ok in other settings, I can play on demand shows on the old TiVo also.
I think the issue may be with my set up on the 4 tv boxes & you may understand if I explain what I have...
Box 1 V6 - Ethernet wired direct to BT whole home disc, the BT disc is wired to the hub 3 router.
Box 2 V6 - wirelessly connected via the BT mesh
Box 3 V6 - wirelessly connected via the BT mesh
Box 4 old TiVo - power line Ethernet connection via one of the BT mesh discs.
I had to install the BT Home mesh discs as prior to using these WiFi was very poor for around the house.