I have double checked that the DNS is correct but when i go to the User Agreement and click yes it just shows a blank screen.
This happened me once. try powering off and on your wii. Don’t try to do the user agreement in the setting menu. If wiilink isn’t working for you after that, switch to the old wiilink DNS:167.86.108.126 and agree to the user agreement there, then switch back to the new wiilink DNS, 167.235.229.36 after that do not click on user agreement with the new DNS. After this everything should be fine.
WARNING: before you do this you should make a bootmii backup off you wii incase something goes wrong.