Who is your "premium BT Wholesale ISP"? They might offer their own digital voice service.
But in general, I think it's better for flexibility to move voice to a separate, third-party VOIP service. Then you are free to switch broadband providers in future without affecting your voice - and also it lets you use your voice service from other locations. If you don't use it much, or mainly for incoming calls, AAISP will be the lowest-cost option. You'll then need either software or hardware for the phone service; I recommended Acrobits Softphone which is a one-time pay-for Android/iOS app. It uses push notifications so minimises your phone battery drain.
Aside: this isn't so much about FTTC to FTTP migration, but rather withdrawal of the PSTN, and associated withdrawal of WLR (wholesale line rental) which let you take analogue phone service from one provider and broadband from another. Even if you were in an area without FTTP, and were sticking with copper, you would still have to migrate your voice to digital voice over FTTC (SOGEA) before Jan 2027.
In your case, since FTTP is available, switching over to that is the sensible thing to do. It may indeed be the only option if you are in an FTTP priority area with a copper "stop sell" in place.
If you want to take digital voice service from BT/EE, you are indeed required to take broadband from BT/EE too. You are also required to use the router they supply, because that's where you must plug your phone handset in. Their voice service is "locked down" so you can't access it except via their router. But since for most people the broadband is the most important part, I think you should take broadband from whoever your preferred provider is. This means taking digital voice either from the same company (if they offer it) or a third-party VOIP service.
Edited by candlerb (Mon 01-Jun-26 17:39:43)