Heater blower motor..Unusual screw

Hi guys.
I have just stripped out cleaned and sorted the heater blower motor on a D2 ( 2002), the chirping has gone. However to remove the motor there are two screws that hold the motor onto the outer shell. These screws had rusted due to historic water ingress and the heads flaked to dust when a tool was applied.These screws are or were bright metal, about 1/8th with half the screw reduced to abot 3/16th. I have never seen any like it. They must be used to center the motor within the housing as when the unit is refitted, if you exert slight pressure on the one of the screws from underneath the slight rubbing stops I can not maintain that pressure with the screw as the head has gone. Anybody know what this screw is called, part number, etc.
I have tried local machine shop in the hope that they could reduce a self tapper and thread it. No chance !!
Failing that has anyboby got a broken blower motor in the shed ?

is it this one? http://www.rimmerbros.co.uk/Item--i-CYP100390L , if not could be AWR6818 but i cant find a pic of that one

Hi S/F
Looks about the right size, but the one needed has the last 1/3rd cut down to half the diameter and threaded. From memory now as I have seen a lot of screws today, the first 1/4 inch is not threaded, and sits in a rubber gromit that cushions the motor case I think to prevent vibration. Probably not self tapping as the hole in the motor itself is threaded to accept the thin part of the screw.
Thanks for looking,

if the thread is M8 then from microcat that AWR6818 seem to look like you say... i can't find a pic unfortunately