Hi Sylvia,
First of all I'm sorry to hear that you've had problems with the Executive Club member not being added to your return journey (or rather added then removed) I have spoken to our Aviation Manager who can see that it was registered against your booking so he's going to speak to our representative at BA to find out what is going on.
In terms of the online check in. You were unable to check in online as you are part of the group allocation (so a number of passengers are on the same reference) and therefore this facility is not available. Some of the group would have been able to use the online check in as they are not part of that group reservation - this may be because they had a connecting flight, it may have been that they upgraded their seat.
I will of course, pass all of your comments on to the team.
Kindest regards,
Julia