Ninthace / Downwind.Maddl-Land, similar to my experience, we had a smart meter installed by SSE, then we changed to Tonik until they went bust and we were switched to Scottish Power, neither of which could see our meter but the basic functions of the in home remote display worked, then we moved to Octopus and after a month they connected with the meter.
I still take a photo of the meters on the first of the month though.