How windy was it whilst waiting around for the race to begin! I found once it started it wasn't too bad and it was only that stretch you mentioned near the end that was hard going.
I managed to get a PB out of it by around 2 minutes so I was pretty pleased with that. You had to keep your head down on the cobbles as it would have been very easy to trip up and trying to avoid stumbling on the tramlines was another obstacle.
My Garmin came up short as well but it is probably to do with it losing reception when going through the underpass.
It was all very well organised but did find it was all a bit manic where the toilets and baggage drop were due to the large number of people in such a narrow space.
Overall I thought it was a great race and really enjoyed the whole buzz of it.