I have recently flown this segment and yes the bar is constantly manned . On our flight we first had our meal and then vsited the bar .There was my friend and myself and for a while a very enthusiastic aviation guy who grilled the barman about his theories about QR for a while .

The rest of the time we had the bar to ourselves before going back to our seats and having a few hours shuteye before breakfast and landing .

I have to say we thoroughly enjoyed the flight except for one problem . It was just too short