A few from the SW (none are as long as the northern ones but there are some quite punchy ones):

The climb from Foxworthy bridge to Hunters Tor via Peck farm, has a bit of everything sticky grass, a boulder field and then when your knackered a trialsesque hoick up over a boulder at 90 degrees.

Lady’s Edge on the Quantocks is a good one, all singletrack with a nice steep ramp up at the end to test the fatigued legs.

If we’re including trail centres the Cwmcarn climb from the start to the top has a good mix of everything.

When I rode it a couple of weeks ago, the bottom half had been chewed up by cattle and was nearly un walkable, let alone rideable.

The climb from Watendlath on the Borrowdale Bash is one that only legends will clean, shorter than some here but it is a classic route, so I’d throw that one in.

Some can be pigs! https://app.strava.com/segments/6408323 Fine until the last left hand bend when it rears up and is basically a rubble slope – think Potato Alley in the Peak. I managed all of two bike lengths then got off and walked.

I think the list needs a range of both difficulty and length in the same way that the road versions do. They can’t all be super hard, you need to have some sort of progression from reasonably easy through to “spend a day working out each section” (Jacob’s Ladder for example)

On the ‘technically easy but still quite knackering’ front, I always huff and puff on this one – Whitewater Dash, particularly the last steep corner after a fair bit of climbing.

Martin Hutch +1.
Dash falls is one of my favourite and least favourite climbs. 😳
Top pic.

Another vote for Garburn Pass &Walna Scar.

good shout

Drum Mountain – from the cross roads just to the North. It’s over 2 miles of relentless ‘up’, some rocky sections to get worked up about in the bottom half, and then the track kicks up in the last third with added water-bars. It’s nearly always windy, but well worth it for the cracking views from the top. The track is then wide enough to race your mates back down on.