I don't know the actual time from the Puma's impact with the sea to the Jigsaw a/c being overhead but I would estimate an hour. The a/c is based on the Miller Platform to the North of ETAP about 45-50mins flying time away.
The fast rescue boat involved is based on a supply boat sized mother ship which patrols in an area specified by a computer program which takes into account wind, tide and sea state. It would not normally be beside ETAP. There is no rescue craft based on ETAP so rescue by boat could also take 1hr plus so crew and passengers have to be dressed properly to survive 1 hr plus in the N Sea in Winter.
In this case they were very lucky to be able to get into the liferafts and not end up in the sea for 1hr plus.