Yes I think I may have lost a place (12th/13th) aswell as I'm sure I would have remembered someone finishing 2 seconds after me. iPod/Nike+ also tallies with the place in-front but I can't be sure because it tends to start timing when it wants not when I press start workout.
I would say definitely try a parkrun. I have done the Milton Keynes parkrun three times and found it to be an enjoyable run with good mix of people ranging from a family with a pushchair right the way through to people in training for major events.