Charter flights go to Corfu on Mondays, Tuesdays and Fridays (and 1 on Weds. from Bournmouth). GB Airways fly on Monday, Weds., Fri., and Saturday. You can book one way on one airline and back on another which gives you more options. Check out GB (from Gatwick). Thomson fly, Thomas Cook, First Choice and Excell.
The only options on Sunday, are Olympic, or Easyjet connecting with Aegean or Olympic through Athens.
You could fly out to Corfu on Monday Sept. 3, and back on Saturday 8th, if flying direct. If you want an extra night or 2, you would have to go through Athens. You could mix and match and go via Athens on the outward or the return, and direct on the other.