Tim, Thank you for your help offer. It seems the TA could finally get access to the P booking class! It took 24 hours but I don’t know to what level it had to be escalated. I am now waiting for the trip to be ticketed to be 100% on the safe side!
What happened at the end of the day… TA contracted a Swiss based TA to issue the ticket for them! So I got it, and the price was even slightly lower compared to the one I initially found on LH.com. So it seems this is now the name of the game: airlines are trying to squeeze clients (pardon my French, I meant yield management) while clients are trying to make their way on this big world…
