The 'local news' shown on certain stations is not based physical geograhical boundaries, but rather it depends on the headend your connection goes back to (image of regions)
This is not something that can be changed, as the headend your connection goes back determines the 'local' news you will see on certain channels.
On parts of the network where there are significant overlaps, additional regions may be available on the following channels:
858 - BBC 1
870 or 871 - ITV
TiVO boxes also access the full BBC iPlayer service, which carries the local news from all regions for 24 hours after they are broadcast.
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV+), Talk Unlim Telco, VIVID 100, Virgin PAYG Mobile