Chrome cast via DD WRT

Hi all, I have spent many hours following multiple websites advise but no joy.

I have my main telecom VDSL router with Uno Telly DNS loaded via Telent.

I then have another router coming off that which has DD WRT loaded. Have been trying to connect iPad and chrome cast to this router so I can watch UK TV. Issue is Chromecast continues to know I'm not in the UK. I have left basic setting on auto. Tried the commands at in admin section.

Any tips would be really really celebrated.

Cheers