This can't be the Police Ian, surely?! Regardless of what anyone thinks of Police, this is quite a new level of unprofessional behavior.
Not forgetting the fact that they're very much result driven, whenever the Police commit to pulling a vehicle over, they will absolutely go over the basics on the driver and the vehicle
without doubt.
If he thought you were even slightly driving too quickly for the situation or using excess speed, he'd have checked your license, insurance, tax, MOT, tyres (ANPR will do the majority of that) while ensuring that you didn't smell of alcohol, that you don't use or supply drugs (any ANPR markers will also do this) and conversate with you to find out why you were driving in that manner (justified or not) etc etc...
Winding the window down, calling you F's and blimes' and speeding off just simply isn't today's Police
Even if they had a higher priority call come through on the radio as they lit you up, surely they'd have driven off before winding the window down or stopped, explained, politely warned you then dashed off (?)
More like travelers with a set of strobes I'd say...