Thanks also for that tip. However running into some difficult issues. Providers I’ve spoken to so far advise the ADSL must be removed before they take over the line. I also seem to recall that having 2 “jobs” on an OR line at once can cause issues, potentially even a full cease.
Unfortunately Plusnet won’t cease the ADSL, as they don’t offer line only, even to cover a cutover. It seems I need to migrate both and then cancel the ADSL with the new provider, likely with 1 months notice.