...and just as an update, on where we are now, our very own 'tech-savvy' Debbie said on 24 September 2019:
TalkTalk is committed to transitioning to IPv6. To minimise any potential impact to our customers and services, the transition will be phased over the next few years as we roll-out new products and services such as fibre to the premises.
We continue to work closely with our network and systems vendors to ensure all new equipment is fully IPv6 compliant. In fact, our network already operates as dual stack, using IPV4 compliant addresses while the major network components are IPV6 ready.
OCE_Debbie speaking about IPv6 roll-out 24 September 2019