Yes, you're right. Mitchell should have realised that as for who said what, it was his word agains the cops and really, it wouldn't matter which way the judgement went, there was no REAL evidence either way. I think the judge was wrong to decide the matter on the balance of probabilities but that's how it is with civil cases.

It transpired that Mitchell did have permission to use the main gate if he chose to go that way and the cops on duty were wrong to stop him.