I have a theory about your time discrepancy - the clock at the finish was missing some lights (or whatever make up the numbers) on the curve of the number 9, because my 39.10 looked like 37.10 which would have been a miracle. So I hung around and saw it change to 40 minutes straight after what looked like 37.59.
First time I've done this one and well worth the trip from Southport I thought. Those views across the estuary were superb. Not a day for pbs with the heat and the wind against in the last mile, but briliant fun anyway.