AFter 9 hours of fighting a new webhosting company, router settings and talktalk I am writing here to hopefully help others. Talktalks supplied routers have no guest wifi. Getting a third party one (archer vr600 in my case) on connetion propogates the DNS vales as 184.108.40.206 and 220.127.116.11. These DNS values offer limited browsing....to the point I cannot see one of my websites (but can see the others)..much better to use googles 18.104.22.168 and 22.214.171.124. I have suggested to the technical department about this. It didnt go down to well, so hope this will help others.
As long as you are aware than using non-TT DNS's deactivates the TT unique features of Homesafe, Kidsafe and TT's version of Scam Protection.
But totally end user choice.
I agree where needed using other dns settings can provide much better results. All depends on the user at end of day not the normal end user will use somthing like this and common that TT will no doubt not update to use 3rd party DNS servers. They have this set for reasons. But again its down to that user who needs.