I tend to use that quite a lot myself being just down the road from me. Pretty much 1100m a lap sticking to the path (prob 1090m), with two sides (South and East) flat as a pancake (ooh, pancake day today!), and the others slightly undulating. But like you say you could extend that a little.
Ducks (especially when people decide to throw their bread onto the path!) and dogwalkers (especially those with those infuriating extendable leads
) are sometimes an issue though, depending on the time of day.