There are some Sky Unlimited customers who are on LLU but retained the land line with BT. New customers however have to go fully unbundled to Sky.
There are even some that went with for line rental to Sky( in the very early days of Sky) and kept their BT line...so BT were out of the loop as regards payments, but not full LLU.
I recently read a post where someone in that situation and was written to by Sky advising that his land line was being "upgraded"....I assumed transferred to their own equipment, and made fully LLU. I did ask if an option was given but did not get a reply. I am almost certain that those in that situation were given an opt out when Sky orignally started connecting to their own equipment, but this was many moons ago.
IMO if there was not a significant cost reduction there is no advantage to the customer but certainly would be for Sky.
As in keeping with the thread I am now going to evict myself...sounds painful..... but it's not I assure you.