That third pitch [your P2] is fairly imaginative route finding, sort of balancing around from climbable feature to [hopefully] climbable feature. And without it being technically difficult I recall that it felt surprisingly insecure and easy to fall off. It must have been quite a daunting effort in 1966 pushing into the unknown, on steep rock, with poor gear, hoping things would turn up. Altho’ it only gains 7 or 8m vertically you finish off a couple of meters further out in space perched on the lip of that roof. There were 3 of us on my ascent, and when we were all crowded on that small exposed stance looking up at the overhanging crack that starts the next pitch the grade of 13 seemed particularly laughable [in a hysterical laughter sort of way.]
If you do go back to get your gear and finish the route I should warn you that one of my seconds commented to me last night that both seconds had thought my finish was 18/19. So it could be undergraded at 17, or it may just be that like many more recent climbers they struggle with jamming problems.