Finally found a way to change my IP address on Cable Modem Telewest
Below link is microsoft way.
My way for Telewest subscribers
Start >run> cmd >enter
New Dos window opens
Type ipconfig/release enter

This releases your IP address
Turn off cable modem or PC or both
Leave as long as possible to allow new user to gain IP
1 hour is enough overnite is a cert
Restart Start >run> cmd >enter
New Dos window opens
Type ipconfig/renew enter

it shows your new IP

Excellent
Wntipcfg.exe: Windows NT IPConfig Utility

Did this as my IP on customers webstats remained constant for at least 2 months.

I would say thats insecure
comments welcome