Only the fibre goes to the head end.
Talktalk's residential FTTP service has no voice component.
"Faster Fibre 150" = G.fast (copper, with voice)
"Faster Fibre 150 without voice" = FTTP (without voice)
"Faster Fibre 500 without voice" (ditto)
However, it's possible their ordering systems are broken, and refuse orders from FTTP properties just because they are not in LLU footprint. If you want the service, try ordering over the phone. Ask for "Future Fibre" which is their marketing name for Openreach FTTP - as distinct from all the other so-called "Fibre" services they offer.