Well, either BT is breaking the rules, or that rule has changed.
It doesn't apply to moves to and from VM cable, as those are cease and provide. Not migrations.
Within the Openreach network it has applied since 20 June 2015, when the MAC process was scrapped.
See Ofcom General Conditions 22
, starting on document page 78. In particular paragraphs 22:11-22:15, where 22:15 specifically says:
22.15 Where the Losing Provider communicates with the Customer in order to comply with this Condition, it must not make any marketing statements or representations in the communication which may induce the Customer to terminate their contract with the Gaining Provider and/or remain in a contract with the Losing Provider.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - AAISP Home::1 80/20. Sync 71288/12440Kbps @ 600m. BQMs - IPv4