Ok, the following are the key facts about my situation
1) I mistakenly sat on a first class seat on a packed London commuter train with a standard oyster card ticket which was valid for the journey in standard class. I made a genuine error in sitting in the seat.
2) I was asked for my first class ticket by a South West Trains Revenue Protection Officer. I said I didn’t realise I was in first class and I apologised that I didn’t have a first class ticket. I handed him my annual rail pass (purchased in Jan 2013 for £1950 for Southern trains and not valid for that journey) and my oyste