What about a Festive 500 as in 500K on the Trails ? Now that would be a real challenge seeing how tough the trails are at this time of year.
I’ve been hitting the trails and I’m up to 122k so far so I might stand a chance of getting near half of the required km’s

Grading is always a bit pot luck, some of it is down to the rider, some riders drop and jump well, but don’t like super steep stuff and vice versa etc.

Some of it is down to the centre, some grade on distance, some on features and some on surface and you’d hope a bit of all 3.

Then there’s DH/Bike Park grading v TC grading AS and BPW (others two, but they’re places I know) are generally tougher than the TCs

Does Llandgela deserve its Black Grading? Who’s to say, one thing that I think is true is that for the most part it’s not especially steep and not especially rough so you can ride it fairly slowly “wheels down” but it’s got a very steep difficulty curve if you add a lot of speed. The opposite can be true in some places, they’re easier to ride if you’ve got the balls/skill to ride them fast.