Am I correct in thinking if I change the time of race it will not come into effect until after the next race, if so is there any way to change the time for a single race to be run this Wednesday?
AFAIK it is actually more than 24 hours from making the change. So it only becomes "the race after next" for leagues that race every day.
In your case (assuming you are posting about the league you are currently competing in) you only race on Monday, Wednesday and Saturday. If you want to change the time for tomorrow's race you need to do it at least 24 hours before you want the race to run.
So if (for example) you want to run it at 18:00 tomorrow so as not to clash with the footie you should do it before 18:00 today. Then on Thursday you can reset the time to normal in readiness for the Saturday race.
