New xud 406 last week.. Electrical problems have struck straight away.

When I turn the key in the ignition to the first position, the starter is turning. ( it shouldnt until the last position on the key)
The car will start, but the starter motor still runs even when the car is running.
I have changed the starter motor for a known good one, to no avail.
I am thinking the igniton switch might be the problem?
Anybody else here come across this before or have any ideas?
Thanks