OK,
Firstly thanks for all the helpful replies (the unhelpful replies were worth reading at least
)
The plot thickens. I've just spoken (again) to NTL. This chap has told me that "although they don't normally do this for customers" I can change my STB for a modem but they require thirty days notice to do it. Initially he told me I would be "sans internet" for a month, then he said a couple of days, finally, I was told that on the day I cancel my subscription (TV) they would arrange for an engineer to visit and do the replacement before the TV service is disconnected.
It all sounds good, but also the potential for major cockups seems to be extremely high.
Does anyone have any advice before I do the deed and cancel the TV subscription?
TIA
Tinribs