The configuration of the two routers together seems pretty stable and reliable. Nobody seems to have anything good to say about the DSL3782. I think the best solution is for me to remain on the configuration I have set up with the HG633 as the modem and the Sagecom as the wi-fi AP if Talktalk can provide support if anything goes wrong in the future.
Hi Tracycat, welcome to the forum, sorry your first post is with a problem . Could I suggest you start your own topic / thread, makes it easier for the OCE guys to help you. When you do could you mention how your devices are connecting, wired or WiFi and the router you have. Good luck Divsec
Divsec, I don't work here, know little, and have too many opinions.