Thank you very much for all your experience sharing!
I am looking forward to my trip in GIB and southern Spain now, and hopefully the immigration is not a problem.
BTW, I am holding a Taiwanese passport, and visa-exempt entry into Schengen and GIB is granted. Just wanna make sure that I won't enter or leave both Schengen and GIB without record.
It's nice to hear that entering the UK is not necessary for my transfer.
Hope to get more breakfast and sleep in the LHR T3 BA gallery lounge!
(Not sure if it is comparable to those served in CX lounge)