Is this not a sign that DMF is on its way out, my pal had something similar on his transit and it transcribed the DMF was starting to go, also started to get a little vibration. Also i had a mondeo which made a similar noise and that had recent had DMF and clutch before i got it, i am led to believe that when these flywheels start to fail they can wear the starter out aswell.

Hopefully cleaning your starter up sorts it.