Just wanted to drop a line explaining that I have a Thomson TG782T Gateway via PPPoA adsl to the ISP which i've placed into bridged mode then reconfiged UT to Router mode giving it a 'PPPoE config type' then inputting wan IP and ISP account username and password' then using OpenDns IPs for the 'Primary and secondry DNS' then configed internal to 'static IP' for the LAN and it works a treat as they were some suggestions that PPPoA is a no go.
So my network is as is:
Net > Thomson Gateway PPPoA (bridged) > UT (router) > GB Switch > SBS2k8 > rest of lan inc VOIP device.
Hope this helps someone out - ping me if more info needed