Hi Falwheeler - and all interested in riding next year's Dartmoor Classic.
While going for June 23 may appear the logical option - given that the event was on the 24th this year - there are other considerations, which may be influenced by which dates other events choose to run on in 2013.
From 2009, the Dartmoor Classic has been held on the last Sunday in June, since when the month has always contained 4 Sundays. Next year however, the last (5th) Sunday is on the 30th of the month. Those who ran events on 1st July this year may be looking at sticking with their first Sunday of the month fixture and going for 6 days later in 2013 or moving a day forward to 30th June. The date choice for the 2013 Dartmoor Classic will be agreed very soon, as will that of the on-line entry system going live and, as soon as they're decided, we'll let people know.