Car always starts perfectly when using a screwdriver to connect terminals on starter motor.
When using the key, however, only the lights come on, starter motor doesn't even click.
But when using the key a short while after having driven the car for a bit, it works again.
Summary: Starter motor seems fine. Key does work, but not when car has been standing for probably around 2 hours.
Car is a 1996 VW Citi Golf 1.3