As far as dates - late in the season ie: mid sept to late oct 2009 might be worth considering ? The weathers still warm, kids back to school and the light is good.
It might be worth noting that our clocks change in the autumn and spring (not sure of the actual dates). This causes our days to become very short during the winter months and we lose daylight very early. As far as Easter goes, it changes every year and I'm not sure how far in advance the calenders tell us holidays etc ? Will do some searching for more info.

Willing to offer any help I can down in Cornwall

Bill