the answer is yes sometimes.It used to be the understanding was it would do a full dlm reset, now we have seen instances where banding has not been removed and the emergence of a "soft" dlm reset which doesnt remove banding.
But in regards to my question, does migrating to a slower product reset DLM and so remove the banding? I am going from LLU to BTW.
It happened to me when moving from EE to Vodafone my telephone number was changed but after 3 days it then returned back to the original number, just give your gaining ISP/voice a call to say you want to keep your old telephone number.