Just a word of caution to anyone who plans on moving to Vodaphone and then porting their number. Most of the cheap deals do not allow number porting onto Vodaphone. The only online retailers I have found willing to do a port are from the carphone warehouse and only if you give them the details at the point you place the order. This is a limitation of Vodaphone that you should be aware of.
Ducky, is it worth highlighting this limitation so nobody gets caught out?