Who is Carol Vorderman?
Anyway, re the original question of this thread : had a quick look at Tiscali's website - it looks like they get you to use 1470,08456614681 as a dial up number - the 1470 is the bit that sends the CLI I was talking about earlier.
So the short answer is that there are no problems in relocating a PAYG account.
cheers.
amofw