alasta: When the wing mirror on my car got vandalised last year I went into the police station thinking that it wasn't realistically worth them investigating but they would probably want to take a couple of minutes to record it on their database in case it could end up providing evidence in relation to some other crime or spate of crimes.
I was wrong.
They made it very obvious that they weren't even going to bother formally recording it unless I needed them to do so in order to make an insurance claim. So, I would highly doubt that they would make a record of an incident like this.
Reporting to the front counter of a Police Station and reporting over the phone are two different things and will be handled differently. I can guarantee you that Police will put a job in if called with the information the OP has provided and they would have done so with your complaint as well (calls would either be put through to Police Communications or the Crime Reporting Line by your local station).
For the OP the vehicle registration would be queried, if there was nothing of interest in the response than a reference to the suspicious person/vehicle job would be logged against the vehicle and the job would be closed or sent through to Intel. Like most in this thread I would encourage the OP to inform the Police of this behaviour so that a reference can at least be logged against the vehicle in case of further suspicious behaviour.
Unfortunately Police Station front counters are often staffed by volunteers or staff who'd rather be else where and they don't have the same service requirements as communications staff for handling public enquires.
Alasta, it is unfortunate that the Police were not interested in taking your complaint, I would hope that you would still report in the future, even if over the phone.