I've just flashed my Draytek Vigor 2800G router with the latest UK firmware, version 2.7. This can be downloaded from:
http://www.support.draytek.co.uk/
Remember to check and select the correct firmware for your router!
I used the default version of the firmware although there are two further variants if you experience sync problems. I connected the router to my PC using an Ethernet cable and ran the firmware update utility - I backed up my current configuration first. I then selected the v28ve027.all file (not the .rst file as this will delete your configuration as well!). The first time round I got a timeout error so I ran the firmware upgrade utility again with a longer timeout (10 seconds instead of 5 seconds) and it worked fine.
The firmware works fine for me. I did make one change to my Internet configuration after flashing the firmware. In the "Internet Access-->PPPoE/PPPoA" menu I changed the "Modulation" type to G.DMT instead of Multimode (which I had set previously for some unknown reason) as per the Release Notes for this firmware.
No problems so far!