As you can see from the results, that’s a real hodge-podge of things, varying from big marine reserves like this to small sites, some of which are already in OSM as something else, and some of which don’t really have a defined boundary.
I suspect that most aren’t in OSM and most aren’t really verifiable on the ground - the only way that I know about Fforest Fawr Geopark is because a pub landlord there told me about it - it’s just the western side of this national park (that is in OSM) and takes its name from, but is otherwise unrelated to, this feature.
I’ll have a think about rendering protect_class-98 features sensibly but I don’t hold out much hope - just a label in the middle of Derwent Valley Mills would not help much, and as mentioned above it doesn’t really have a solid boundary.