I use the DV120 routers successfully with Mikrotik, please post screenshot of the WAN configuration screen on the Draytek, and your /ip firewall entries, as well as your PPPoE setup. I should be able to figure it out for you.
Also, what firmware version is on the Draytek ?
I did not realise PPPoA was used in the UK, I thought it was all RFC1483 bridging(aka MPoA)…
Thanks - it was just a simple masquerade error after all - on the wrong interface. I am impressed with the Draytek though - like having a built in modem in routerOS.