In the OPs scenario it isn't much help. He may as well order a data only FTTP service from his provider of choice and then port the landline number to a VOIP provider of his choice which will also terminate the FTTC. This can easily be timed to have no downtime or even a small overlap in services in case an issue arises.
It will have the same outcome but cheaper and with the freedom to choose any broadband and/or VOIP provider they wish.
On my FTTC to FTTP migration, Zen to BT, wishing to retain my LL number I chose the easiest option at the time, BT's BB & digital phone package, worked very well, seamless migration.
However, now realise that I should have migrated my LL to VOIP provider first, retaining original number in order to achieve more future flexibility with BB provider choice.
Regarding "j0hn's" suggested solution of moving LL to VOIP (retaining number) and moving to another BB provider, not sure of the logistics that would be involved to ensure minimal/no interruption to BB/LL services.
If I order BB only service from my chosen alternative provider can this be implemented simultaneously with my existing BT BB & LL service?
If so would this use the existing fibre run CBT to house, in my case UG feed?
Could two different ISP services co-exist on the same fibre run assuming that was permissable?
Would a second ONT be fitted?