Stuart
Tried to setup the races to be so it ends on the 24th and start racing again on the 2nd. Somehow we ended up with the 7th, then tried to change this and it then moved again.
Assuming you race daily, then to achieve this you would only select the race on the 25th and set its new date to the 2nd. The system will figure it all out and postpone all the races in between for you.
I'm going to take a guess that you probably attempted to move the races one-by-one in reverse order, which will result in some races being postponed multiple times. E.g. if you move Race A from January 1st to January 2nd, then move Race B from December 31st to January 1st, Race A will likely have moved back twice, and now be on January 3rd, as everything after a race that gets postponed also gets postponed. With each consecutive postponement 'Race A' will get further and further way, until it lands on January 7th or something, which I think is what I saw on your league.
It's only necessary to select the race at the beginning of the period you want to open a gap in, then postpone that race to when you want the period to end. The system figures everything else out for you.