Hi Graham,
Which browser do you use to access websites?
I know how it feels when things don’t work properly.
Placing a check on the option for A utomatically detect settings may help in getting the issue fixed.
Perform the steps suggested by naccachetrading from the link mentioned below and see if it helps.
If you need any further assistance, please post your query on Microsoft Community Forums and we’ll be glad to assist you with it.