Well, that was tough. Despite feeling like I was about to puke for the first 5km and having the British 10 mile TT champion (I think) lap me after 3km (despite starting two minutes behind me), I still made it around the two six mile laps in a PB pace.
The course was relatively flat and more or less impossible to get lost on which was good for my first go at something like this. I'd the option of doing one or two laps and opted for the latter just as I past the start\finish line.
I tried to focus on keeping a high cadence, setting a minimum limit of 85rpm (before shifting up) and a maximum limit of 95rpm (before shifting down). This strategy seemed to work well for the most part, with just one minor hill causing trouble.
Here are the stats from my Garmin.
Time: 39m 03s
Average Speed: 28.8kmph
Fastest Pace: 1m 40s per km
Average Cadence: 87.6rpm
For a brief perspective, my usual cadence is just under 80rpm and my previous best average speed for a comparable distance is 27.9kmph (average cadence for that ride was 79.4rpm).