That's not a change to T & Cs. The orice rise is well known,
as is the fact you may not be aware of that the price rise within contract enables people to leave without penalty, as long as they notify within 30 days of being personally informed by letter or email that it is coming. (Ofcom rules for all ISPs). No need to pay off the required amount stated in the T & Cs.
Many people do take advantage each year and migrate for a better deal elsewhere, then move again elsewhere or back when their new ISP raises their price within the contract period.
All that BT have done is offer you a retention deal early, to stop you leaving.
Line rental and broadband prices now have to be added together and presented as one figure when offered in a bundle. If you look at all the big boys' websites you will see they all do this. Only where broadband is offered with the line rental with a different provider is it not included.
Kindness isn't going to cure the world of all its awfulness but it's a good place to begin. Daisy Ridley.
My broadband basic info/help site -
www.robertos.me.uk. Domains, site and mail hosting -
Tsohost.
Connection - AAISP Home::1 80/20. Sync 54999/14466Kbps @ 600m. BQMs -
IPv4 &
IPv6