How the UK law stands with the Section 59 Police reform act. ?

[Heather B]

Bit of a long one this but I don't know where to turn without seeking legal advise that I really cannot afford.
My son passed his driving text last week and has been driving my husbands car. Last Thursday the police appeared at the door to speak to either my son or my husband, both were at work. They told me that they had received a phone call off an hysterical girl saying a car was flashing and beeping at them and then she got cut off, they had traced her number the next day and she said she did not want to press charges. I was naturally shocked, when my son came home I questioned him, he was actually shocked, he said he had been flashing and pipping his horn because it was his old mate from school and they had actually pulled over and had a chat and he had even talked to the girl. Now I know kids lie but I am a pretty good judge of whether he is lying or not and I believe him. He said he would explain to the police when they came back.
I told him in future it was pretty silly to flash the lights at someone uin the dark as it could un-nerve them and he said he hadn't thought of that.
Anyway the police came back the next day, my son was still at work, they spoke to my husband and I even told them what my son had said and I wondered if the girl had over-reacted and then felt stupid next day, they said this could be the case but he was being issued an anti-social driving slip, a section 59.
Anyway, on the way home from work last night he tried to over take a vehicle in a 60 mile zone, the vehicle was doing 50. Unluckily for him it was an off duty inspector. He made my son pull over on the road and then proceeded to shout and swear at him and threaten to hit him (this was witnessed by his girlfriend), he then said 'no I've a better idea, I'm signing on work now and we'll seize your car'...which they did, he called for backup, my son called us and his Dad went down but they didn't want to know, they just took the car.
I have just come back from collecting it at a cost of £117, and the man at the recovery depot informed me if he gets done again the car will be crushed.
How the hell is that legal, its my husbands car which cost £3500 2 months ago. If my son had been doing idiotic dangerous driving thats one thing, but what he has been done for is crazy, and they have no intention of even going to speak to the people in the first case to see if there was any truth to it. Also how can an off duty cop on his own do this?
Any help at all would be much appreciated.