thanks for your help.
i can access the manager typing 192.168.1.254 without a problem, and that is what is shown in the display at the top of the screen.
however, i usually type bthomehub.home and its when i do that is comes up as website not secure - im sure this is just the latest security feathure of iso 11.3.
i'll just stick to accessing it through 192.168.1.254 in future.
Don’t use bt homehub.home!
I can dig out some old posts on this topic, if you wish......Or you can do a google search, which will show discussions.