A couple of years ago, Nick Craig and a few others (Paul Oldham, a chap called Martin Brookes (aka dibley off here) and a guy called Neil from Hope Technology) did it for What MTB. I was also there with them and witnessed Nick, Martin and Neil clear it in one go from bottom to top, no dabs. Paul gave it a damn good shot but didn't quite make it. I came no-where close!
The MBR article was basically a rehash of that and as richpips said, they all did it in sections but by the end of that were too knackered to do it all in one go.
The first part of the climb from the bottom to the sharp RH bend is the most difficult. It's mostly luck as to whether you clear that or not. the middle third is "easy" (relative term!), the final bit from the gate to the summit has a couple of easy flattish bits and the brutal cobbled climb at the end. Do-able but you need to be technically VERY good and have an exceptional level of fitness.
I take any forum claims of people clearing it with a hefty dose of scepticism seeing as even Nick Craig has only ever cleared it in one go on about 3 occasions.
I've made it (clean, in one go) from the bottom to the mid-way gate on 2 occasions out of dozens of attempts over the last 12 years. Both times it's left me too dead to finish the rest off in one go although in small sections it is (mostly) do-able with suitable rest in between!