Eaglenest,
I mentioned DLM to the latest tech and she didn't know what I was talking about. She did say that they had installed a 'booster' to improve drop out performance but couldn't tell me when. I gather it was fairly recent i.e. 2016 and as my issue started before last November I don't think that would be a factor, except, maybe, for the better. As far as I can tell it's made no difference. I've now given up on Telstra and will investigate other options but I'm not optimistic.
Thanks for input and concern.
Regards
Statek