On Sky in Bicester, despite my BBC and ITV being South, my local inserted adverts tend to be Bedfordshire, Buckinghamshire, Northants, and Warwickshire.

Part of Bicester where the majority or aerials are on Sandy Heath, not Beckley,

Part of Beckley's function was to provide Midlands to areas of Sutton Coldfield's footprint that couldn't receive it.Beckley covers parts of 4/5 other regions. Again, topography wins as areas of East Oxford, and the City Centre can't receive it yet on higher ground, 5 transmitters can be received.

I live in Bicester, and there are also aerials on Sutton Coldfield and Crystal Palace. If you go north West out of Bicester, many villages are Sutton Coldfield due to the hills. I could pick up Sandy Heath in Oxford on a loft aerial.