This one is out of left field but I've seen it work,(turn the ignition on but don't start it until the seatbelt light

has gone off).

It had something to do with the computer needing to "catch up",( that's how the auto elec explained it to this

guy),

If it's a quick trrrrr,trrrrrr,trrrrr I would go with the faulty Alternator as my OH just had hers replaced in her VX due

to the similar sound,(once I recharged the battery it started fine but the Altenator was faulty).

I used to carry a screwdriver to cross on the starter motor,(these days those sort of "fixes" would possibly blow

the computer systems in the newer cars).