Although I will not question your reasons or responses...you have suggested that the Plod couldn't see you...not that you hadn't driven through the cones.
If the cones were in place, certainly on the RHS of the road to stop vehicles ENTERING the area then you must have driven past them and done so on the LHS of the road.
I dunno about the bollard and pedestrian crossing but if they'd been placed in a position where you would have to drive on the LHS past the bollard and pedestrian crossing, you must have done so.
The plod may have been tired, narky, cold, slapped by wife...I dunno. BUT, even if you can prove he didn't see you, you did still drive past the cones, bollard and pedestrian crossing to get to where he was...so you did contravene the traffic laws.
The mitigating circumstances are that you were trying to find a route home and wanted to speak to him. You wanna try throwing yourself on the mercy of the court for 3 points and £60?
I'd take the hit. I'd be furious, especially if plod is being devious about seeing you, but the fact you were there proves you did as he said.
Either way...best of luck.