Hi
Sale of goods act doesn't apply to commercial purchases so there will be a separate contract in place. I suspect that contract will not include things that can't be added now that wasn't part of the original equipment.
The blame is squarely with BT for commissioning VDSL without everything working from day one, they cut corners at the beginning and installed VDSL Lite, so we have no vectoring (apart from some exceptions) and no G.INP on ECI cabinets. This sort of things is repeated all the time, commercially and in retail, where we buy a product that is missing a "feature" that will be enabled later by a firmware update, which either happens late in the day or often not at all, and usually fails to work very well if it is implemented.
G.Fast is the same, corners cut and we now have pods at the side of cabinets and no reduction in line lengths for anyone. ADSL was also similar, Seamless rate adaption was an option they missed out, and they also never implemented PhyR retransmission on ADSL, which is what G.INP is today. So G.INP, a technology available a long time ago on ADSL, is still absence from a very large percentage of VDSL lines.
It's about time BT stopped messing around with corroded, unshielded, hardly twisted paired cable that wasn't much good for audio let alone data, and got around to upgrading the infrastructure for the 21st century.
Regards
Phil