I don't know what times your flights are at but if it helps you can fly BA from MAN to LGW. Departing first thing in the morning on January 10 and returning last thing in the evening on January 24 currently works out at about £450 for six people. When split six ways its not financially crippling although I know it's extremely galling when it's TCD's fault. If this is a goer for you book now and get the cheapest possible fare.