***UPDATE***
So i have parked this for several weeks due to holiday and other projects and decided to pick it back up again today. Went onto the Draytek website and saw that a new firmware was released in the last few days, looking through the release notes i found this...
Improved interoperability of Ethernet WAN2 interface
So i connected the Draytek back up and tested the issue as before, when the WAN2 connection was 10/100 lots of packet loss and speedtest wouldn't run, upgraded the firmware and BANG...it started working!!!!
So after hours on the phone to Draytek support and them not believing there was an issue it looks like they finally fixed it. As you can imagine im a bit annoyed that after so many hours on the phone and site visits they didn't even bother to call me and tell me about the new firmware.
Anyway, issue resolved