There are trails of similar difficulty to the ones in the video in the tweed valley, and the witches trails amongst others. Just because they aren't well known and not signed, doesn't mean that they're not there.
secrets and lies is prob more technical, def lot less room for mistakes between trees and only a foot wide trail to ride on. The 4 linking trails from ewok village is also steeper. No comparison overall on the trails with whistler way ahead, just saying if you look then there is trails out there in the UK that have this level of difficulty

