I would think you could move your FTTC away from Sky to any of the many ISPs that don't require you to put your line with them, as Sky do have stand-alone phone rental/calls. The problem would be if breaking the bundle creates a new minimum term for the Sky Talk
If it doesn't, you then simply move the phone after the FTTC migration. Is there anything in their T & Cs about it?
Have you specific providers in mind?
My broadband basic info/help site - www.robertos.me.uk
| Domains,site and mail hosting - Tsohost
Connection - Plusnet
UnLim Fibre (FTTC). Sync ~ 56.6/14.1Mbps @ 600m. - BQM
"Where talent is a dwarf, self-esteem is a giant."
- Jean-Antoine Petit-Senn.
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.