Trail centres are what they are. Groomed and generally all weather, and places you can kind of trust.
All the regular ones are still what they were, and generally with British trail centres a black grade seems to be more about length and technicality of the climbs or descents, but not about some big scary features.
BPW is different. It’s not a regular trail centre. It’s half way between one and a DH venue. It does have “features”. Descents on the blacks can be challenging and certainly beyond and risky for some riders which is why they’ve added qualifiers on them now. The blues and reds though you can certainly ride on a hard tail. Not comfortable, but you can do. Some people though rock up on big DH rigs but then regret it as the place isn’t full on DH and requires pedalling in places.
Compared to “natural” stuff (it’s never natural really, someone’s done some work on the trails or paths, bridleways, it’s just not groomed), it’s still very different. My local is Surrey Hills and it’s riddled with all kinds of trails, many rough and raw, and a lot of constant change. Conditions change the trails a lot and local trail builders do likewise. You can’t exactly trust a trail to be the same each week.
Having done a little raw out in the wild stuff in the Lakes and stuff around Brecon, bits in Devon, again trail centres and bike parks are nothing really like it. Except maybe BPW has Rim Dinger which does remind me of the crazy loose as hell rocky bridleways in some places.