Hi Darren,
Agree, staying within the BT products was my original idea but looking at the range between the main house SH2 (front of house) to the garden annex will be some 60m away through the majority of both properties i didn't feel adding additional wifi extenders was going to work (especially as the annex is timber frame with aluminium backed celotex insulation so somewhat a faraday cage).
Also the wifi only (no ethernet ports) option would restrict the connectivity of the legacy peripherals (printers etc) and the connection of the BT TV main box needs GigE connection if I'm correct?
I like the YouView boxes idea though so will look into this thanks
If I'm missing something in your suggestion please let me know as I'm not anti BT I just couldn't see any obvious solution 🐵