With regard to the channels, there are two issues. The first is to do with contracts; at the moment, while the two networks are separate, then the previously agreed carriage agreements remain in force, and Telewest didn't have agreements for these channels. I would imagine that ntl:telewest's lawyers are working overtime at the moment getting new, universal carriage agreements worked out with all the channels, but until that happens these won't be added to Telewest.
As I recall, there remained differences in channel provision between Langley and Bromley for about a year after the CWC takeover, so I wouldn't hold your breath
The other issue is with regard to there being enough space for any new channels to be launched. The ones listed above would require at least a couple of new transport streams, I would have thought, meaning new equptment needing to be installed in every Telewest headend.