A couple of us had a look at these over the weekend. The 'bolts' are indeed resin anchors. Not certain of make as I'm no expert but would guess at Fixe
P Anchors. Unfortunately they were install incorrectly with the bolt head being proud of the surface rather than the welded part set down into a groove. Apologies if I've explained that poorly. I've used them a few times recently and they were solid so it's within the last couple of weeks they've worked loose. They only move a couple of mm but clearly that's not how things should be. I believe the current bolts were installed by a local climber who also does a bit of caving on the island.
On the whole the local climbers (who taught me how to install bolts) use home made staples from 8mm 316 stainless bonded with Fischer 410 C vinylester resin.