I contacted Telewest a few years back when I bought a brand new house about installation - stupidly thinking they'd probably just install the cables when building the houses, straightfoward enough?
I was then told that generally cable companies don't install cables until the last house on the development has been up for 2 years. Yeh right - they wait til you've got a lovely new road/pavement - dig it all up and only then do they install cable!
Needless to say I went with Sky