My memories of flag towing on 34 Sqn at Tangmere were of an operation like this. We nominated a "banner party" who took the landrover to the touchdown end of the runway, stretched the banner out beside the runway then towed the towline along the edge being careful to avoid any lights etc. When the tug arrive it taxied down the runway until instructed to stop by one of the banner party who then nipped under the tail and connected the rope to the bomb release mechanism at the rear of the ventral tank. Meanwhile at the other end the banner would be laid out on the runway. When given the thumbs up from that end the aircraft would be marshalled forward to "take up slack" which would pull the towrope onto the runway. When OK at a signal the tug pilot would set 11,000 rpm, release the brakes and make for the wide blue yonder. As for being a tug pilot, any young Bloggs did it. The signal to drop the flag was given by the runway controller.
On one occasion the flag was prepared waiting for the arrival of the tug. The landrover had recovered a just dropped flag and dropping one end of the towrope at the hook up point ready for a future tow slowly drove back to the banner end paying out the towrope, then parked by the runway for a quick fag, as one did in those days. The tug arrived, I signalled it into position, hooked up the towrope, took up slack, the landrover began to move backwards, its door were flung open end two figures leaped out. Wrong towrope !! Oh how I laughed.