So have completed online check in for the GLA-LGW leg, but will not let us do online check in for the LGW-MCO leg. I confirmed all contact details but comes up with a message saying we have to show passport to BA staff at airport - assume GLA. I have read some other threads saying nothing to worry about, would have liked to select our seats but OK if not assigned together. Should I be concerned? have never seen this before with BA.