There is a semi-airside connection route in T1 .. but you do need to re-clear security ( unlike in T2 ) .. It's at the end of the T1 baggage call closest to T2 , beside Baggage Belt number 1 .. there's a stairs up there and a doorway which takes you into the top of the T1 security queue .. It's not open all the time, but it is in the morning definitely ... It's probably quicker than exiting out through customs and going upstairs and re-entering security .. but not by a lot. To the OPs question though the transfer facility here ( and in T2 ) has no airline desks .. if you haven't got a boarding card for your onward flight you can't use it .. you'll need to go landside and get one