How did you not know?
Surely, at supply league, the official in the middle would have had a notification about and more likely brought it up in the changing room.
Also, the observer would have met before the game (unlike the 5-7 schemes), listened to the pre match etc before letting you get on with the pre match changing, warm up etc.
And he or she will then make an appearance in the changing room to discuss the match with middle and clarify anything that may need clarifying.
Unless I missed this, I assume this happened?
If it did, did you not realise he would also observe you too?
Saying that, well done on the 74.
I find this to be the average I see most weeks. I was fortunate enough to get an 80 last season, and most recent was a 78 but 73-75 is what I see most weeks with very little developments but all comments are very helpful, good or bad.