I have (attempted to) check in online for a LHR-ZRH flight tonight from T5. All went wel, but at the end no BP was produced because they need to check my passport at the airport. I presume the reason is that this is the final leg of an intercontinental flight, where the inbound into London was already several weeks ago.

My question: what is the latest time by which I have to be at the CKI or the ID check counter in T5 to have my passport checked? Not the "we recommend", "I usually do", "we've had problems when" time, but the time by which British Airways computers no longer spit out a boarding pass if I don't turn up at the CKI or passport check counter before. I am familiar with the conformance requirement of scanning the BP at security control 35 minutes prior to departure, also with check-in deadlines of 45 minutes for European flights, but not with deadline for this "you are checked in but not really" situation. Also 45 minutes?

I'll be using the First/Gold area in T5, so waiting lines shouldn't be the issue. I do not check any luggage.

If everything goes to plan I'll be there 70 minutes before departure anyway, but there is some possibility that things do not go as planned. Just asking for tranquility of mind, in case I arrive at the airport later than anticipated.

Thanks.