I spoke to Vodafone who told me to go through the following steps with my router, I guess I'll do this when I get home later, although this seems to be different to what everyone else has been told.
Thanks for calling us today, this is to confirm how to change DNS from GUI page:
1. Go on to your computer and enter the number 192.168.1.1 in the address bar of your browser, this should take you to the log in page for the router and not a search result page.
2. The password you need to log in is 'vodafone' all lower case.
3. Once logged in, in the top right corner you'll see that it's set to Basic Mode. Click the drop-down and change it to Expert Mode.
4- Click internet in the red menu bar. In the left corner choose DNS/DDNS
5- Change the configuration from Automatically into manually.
6- Type in the first line ?8? in each box
7- Type in the second box ??8?? in the first two boxes and ??4?? in the last 2 boxes
8- Then click Apply at the bottom.
Thanks
Vodafone team