TUI require the PLF reference number to check in for the return they also check it on check in in resort. They annoying thing is that you have to enter your seat number but unless you’ve selected your seat you can’t enter this so can’t complete the form. You enter a fake seat to complete the form to enter into the TUI system to then check in. You are then supposed to complete another PLF as the seats have changed. This generates a new PLF ref but no way of entering this into the TUI system! There must be a better way