Not flat that course is it!? Did it once last year I'm hoping to put myself down for a couple this year....
Did a xoulpe of laps of clayton vale tonight on the way home from work. Dryza bone and very fast. Still got sundat in me legs though....
Hmm.... it has a few small rises such as the bridge of Chelford railway station, but they really are small rises, it is the fastest local 10 course as far as I know and the most used, generally a club 10 on a Monday and on a Wednesday on this course. Course map here:
http://app.strava.com/segments/1339761
Maybe you are thinking of the J2/3 (course map here:
http://app.strava.com/segments/1078016) from Tremlow, along the A53 to Chelford Island, that course is more lumpy and slower (read: sporting), last time I did that course was back at the start of the season, I did ~25 mins, could do under 24 minutes now. There are a few mini hills, can be taken on the tri bars and you probably won't dip much below 20mph unless being smacked with a headwind too.
The course to avoid if you want fast times is J4/20 (course map here:
http://app.strava.com/segments/2451539) it is the most technical and the lumps are placed right where it hurts the most, i.e. right at the finish where you are to go over 2 motorway bridges. Personally, I enjoyed this course the 1st 2 times I did it, it is not fast but it is quite technical in parts, but my enjoyment was tainted when I rode a makeshift 25 doing several laps of it (because there was roadworks on the intended course) into a savage wind. It was awful coming up over the motorway bridges, the rises kick you in the gonads, then the wind as you hit the exposed section kicks you in the teeth as you drop to your knees
Basically:
J2/1 = Fastest
J2/3 = Lumpiest
J4/20 = Most Technical