I'm going to continue running as is (new DNS setting) for the next 3 days to be confident of the stability, then I'll reset them and test.
Milo, thanks for your input. I'll keep that in mind.
In my Netgear box was my my old Netgear modem/router, replaced by current one 4 years ago. (No I'm not a hoarder - it does have a symbol showing not to be discarded in rubbish
).