Just wanted to point out that the settings I posted in my original post were correct and I put the problem I was having down to a signal problem. The problem basically solved itself and I've been using giffgagg ever since.
Follow up Post:
A couple of people on this thread asked what the VM202 is like to use and I just wanted to say it is a great phone when it works, but it does not have good singal reception. We have three different giffgaffed phones in our house - VM202, LG KS360 & Nokia 6070. The VM202 gets a much poorer signal reception where ever we go and at home the signal is just terrible. As I'm at home a lot (including during the day), this is a big problem and I'm thinking about changing the VM202 after only a few months.
I'd not recommend it to others now.