Re: Switching ADSL
why not change the way LLU works, put the DSLAM on the openreach network and have that part controlled by openreach. Once your cable is jumpered in you're set and moving ISPs is just a question of reprogramming which back haul service your packets run over.
People said this wasn't possible with mobile phone numbers but you can get those ported inside 24 hours.
Even without changing anything moving ISPs should be a <24 hour job.