I'm booked on the BA1407 to LHR tomorrow, and then on to the BA253 On Tuesday, When I have come to check in, it states checkin is unavailable due to; "Sorry, we cannot continue to check you in online for this flight as we are unable to offer you a choice of seat at present.

Please proceed to the airport."

Does anyone have any insight as to why this may be? Also when doing online checkin it stated that I have to use the Terraces lounge at gate 1 instead of the First lounge below the Concorde room. Is this still open to Club Gold Pax?