Hi guys, I have a Desire 310 but the single sim 512mb RAM model (D310u).
Was not able to unlock bootloader, but using either MTK Droidtools OR Root Genius I was able to get root successfully. Both tools worked without bricking the phone and without unlocking bootloader.
Am still working on getting a recovery mod installed though, cant find a way to get CWM on yet..
If you have found a way to get a custom ROM on this thing yet, I would love to know