The 3 behind the desk, or bench, would be Lay Magistrates, which I think is johnw's position. One person would have been the Clerk to the Court, who's job is to provide legal expertise to the Mags and the other one would have probably been an Usher.
Although it's so long since I've been in Court I've forgotten what some of them do.
For instance, before the law changed regarding vehicle taxation, I was in Court when a man had been caught driving with a Tax Disc that was several months out of date. At the time you could keep a vehicle without an in-date RFL as long as it wasn't on the highway. There was no SORN at that time.
The defendant had been using a company vehicle so hadn't been using his own. He changed jobs within the same firm which meant he had to use his own car.
He supplied a letter from the Council to the effect that the road it had been parked on for several months was not maintained by the Local Authority. A letter from a Garage owner on the same unadopted road to say the car had been parked there every day he could remember and one from his employers to confirm he'd had unlimited use of a fully expensed company vehicle.
In Court, he explained all this and showed the letters confirming his story. The Clerk explained the legal situation, namely that the law (at that time) required any driver found on the road with an out of date tax disc to pay all the outstanding duty back to the expiration of the old disc, plus tax it for the current period. There was no way round this, as that was what the law stated.
The Magistrates took this on board and decided that only the back duty should be payable and waived the fine, which would have been about twice the outstanding duty, and the costs. Had the defendant appeared with a bad attitude, or not bothered to appear at all, he would have copped for the lot which would have been about £350. As this was in about 1995, that would have really hurt.
Perhaps the important aspects are that, a) he pleaded guilty, but with extenuating circumstances, b) he bothered to turn up, c) at no time did he show any malice towards the Cop who nicked him and d) he put forward a credible reason for his lapse.