I've not been into Hades, but I've been past it many times (it's on one of my scrambly runs).
I wouldn't be too keen on abbing in from above, as the anchors are right by the path, which is frequented by all sorts. I know folks whove had bags nicked from the grass while they were belaying. The anchors are a bit funny, and I'm not sure how straight the ab is.
The straightest line down is from a little v notch in a rock wall. You can look over the fence, there's a gap of about 4 feet, then a spindly tree and and the little wall. The rope would take you down easy slab, then through a gap in a vegetated ledge down a couple of short steps onto the large ledge with the cave. Places to rebelay may be limited due to some misguided soul doing some comprehensive vegetation clearance this spring. The anchors would be either the fence (hmm...), the spindly tree (not sure I would!) Or extending the anchors to sturdy trees across the path (potential to trip pedestrians)
At the top of easy slab, there's also an open area with a nice view and two sturdy trees. You're much closer to the undercut edge of the buttress here and could swing into space.
I'm not sure which route you tried to climb up, but the first "pitch" of easy route is considerably easier than either of the fir tree slab options.
Hope that gives you some information to help you with your decisions.