I've spent nearly all day trying to get to work as either Repeater Setup or AP-Bridge Setup. To complicate matters I also want the computers to use the 2820 as a DHCP Server. I managed to get the two to see each other once, but haven't managed to replicate it. I thought this would be easy with both products be Draytek. Was I wrong. Any ideas anyone.

Does this help?
http://draytek.co.uk/support/kb_wlan_AP700_UniversalRepeater.html

Thanks for the link the issue was the passwords. Unfortunately the PC's connected to the AP700 wont connect to the internet. Any ideas?

I've a 2820Vn and an Ap-700 that I've had running in WDS-Bridge. I remember it being a bit of a pain initially, but followed the guide that's already been linked to.

Is it a case of a bad gateway being specified?

Firstly make sure you're using WPA2 if possible - if that's not helping then try changing the channel that the AP and router are on to avoid interference - if that Still doesn't work then put the 2820's wireless bandwidth down to 20MHz which you can set under Wireless LAN - Advanced Setting by setting the Channel bandwidth to 20MHz, that usually helps.

Also make very sure that the AP700 isn't plugged in to the LAN directly still, that'll cause a network loop and general badness for the whole network.

Thanks for all the suggestions. Finally managed to get it working using the AP-WDS setup. Although the 2820 is showing as D when I checked the Link status.