hi david
i got 2 suggestions from my side.
I donno why you are using this ip as dns-server in your router. remove this and use 212.159.6.9/10 instead.
dns-server 192.168.1.1 212.159.6.9
i hope that should solve your dns issue.
if you still face issues with browsing then try applying the below command onto the router so that it can forward the packets to the SP.
ip route 0.0.0.0 0.0.0.0 dialer2
regds