In reply to Joel Perkin:
Hi Joel
Well done on getting your mate out of the situation one way or another.
Others have provided greater detail of how to do it.
But as someone said above, looking at the log book of your second, I wouldn't have taken them on Spiders Web in the first place until they had had plenty of old school HVS-5a seconds under their belt.
Spiders Web is a route I know very well. I have led and seconded it with ease and led and seconded it with considerably less ease - much dependent on conditions and mental attitude on the day. It's an old school Tom Patey piece of brilliance which is thin and quite exposed in places.
One of my worst ever climbing experiences was seconding a mate of mine on it on a hot and very sweaty summer's day 20 years ago when I had forgotten my chalk bag. I got to the crux on pitch 1 (the step across around the bulging arête onto the slab) only to find it very slippery, covered in lichen and that my eejit leader had decided not to place any runners between the start of the crux and the belay (circa 15ft?). I took out the last piece of gear and saw the loop of rope between me and him and the potential huge pendulum down and below the roofs. The rock was so greasy, it felt marginal. I was terrified. He thought it was funny and told me to man up. I made the moves, raged on arriving at the belay and never climbed with him again. Very bad leading.
The second pitch on which your mate had difficulties is not easy because it weaves right (via that thin step over onto the slab) to gear, then up, then back left a long way under a 3-4 foot strip overhang, which further overhangs and overlaps above that, which is completely out of sight from your leader. The footholds are thin going leftwards towards the arête with a lip of a roof and void below. There's gear in the crack running along the overhang but it's easy to block some of the handholds. It's also easy for the leader to create very bad drag (for themselves and the second) - and to make life hard and scary for the second.
When I last did it (second) a few years ago, the leader protected it such that the right hand rope (looking in) ran in a straight line upwards over the first part of the traverse and overhang above, which provided some comfort. But I was almost pulled backwards into space (due to the overhang above) when he took in too tight. In the meantime, there was drag on the left rope and he left long loops of slack which was somewhat disconcerting. He couldn't hear me because I was below the overhangs and I ended up screaming for slack on the right hand rope and take in on the left hand rope.
If my second fell on the P2 traverse, I wouldn't want to lower them to the ground if at all possible. At least one rope would be running over the overhangs/overlaps then the edge of the 3-4 foot strip roof, then the lip of the roofs below.
Generally, I'm not a fan of the Dewerstone. It's seen as a nice, easy, safe crag to build up through the grades. But on warm, sweaty days, the rock can feel smooth and soapy and has far less friction than the Haytor area. In the last 10-15 years, there have been some fatalities and major accidents there for whatever reason (at one stage, it seemed there was almost one a year) - a disproportionately high rate on local crags.
I once witnessed someone who was seconding - yes, seconding - deck from 40 feet (conjecture - leader had slack in the belay system and when the second fell, leader was pulled forwards and possibly over the edge and let go of the rope? - this happened to a friend of mine from Uni at Almscliff years ago). I assume and very much hope the second survived because the police never called back for a witness statement.
Incidentally, if you want some other Tom Patey classics down here, then there's Sarcophagus and Chudleigh Overhang at Chudleigh (neither of which should be underestimated for various reasons), the great Outward Bound on Lowman (burly first half into delicate second half) and the brilliant and very well-protected Leviathan at Dewerstone.
Have fun.
C