wrong offence code???

[summers08]

last night i was on my way home from the city centre following a friend of mine that was leading in front as i wasn't familiar with the roads in that area.

i followed my friend up a one way street(the wrong way) and did not realise untill it was too late. my friend pulled out of the road and continued and i stopped to turn around, a police van came around the corner a few seconds later.

a police officer got out of the van and asked what i was doing coming the wrong way up a one way street, so i told him i had realised when it was too late and that i was finding the nearest place to safetly turn around, the officer said ok son i will just give you a caution this time, reverse back down and be on your way.

i started to reverse down the road and the officer started waving his hand for me to go back to him so i did so, he then told me to get out of the car and said that he was giving me a ticket and 3 points. (he whispered to me that it wasn't his coice but his sgt told him to once he had let us go) i then asked him if the full road was a one-way road to which he replied "yes". i later found out that it wasn't but only the last 20-30 yards were a one-way street. he then asked for my documents which i did not have so he gave me a fixed penalty of £60 and said i would get 3 points and i had to take my documents to the police station within 7 days.

on the fixed penalty he wrote offence code:4 goin wrong way up one-way street and then went back to the van because he did not know if it was the right code. his sgt made him change it to code 91. he then said be on your way and made me reverse back down the one way street.

i am wondering if i have a leg to stand on because:

1) he gave the penalty with false knowledge (said all the road was one-way)

2)originally let me go with a telling off and change his mind due to another officer

3)if code 91 is the correct code and what code 4 is?

4) the incedent was a pure mistake due to lack of knowledge about the area.

5) he told me if it were up to him he would let me go with no fine/points