If what they say re MOO is correct re immediately terminable contracts then it makes MOO a rather pointless, hollowed out concept, since when does anyone work for free without consideration (to create a contract in the first place) other than as a volunteer working for free when there will be no tax issues in the 1st place.?
Also, the fact he was skilled means substitution was possibly neutral per Mitchell and another v HMRC  UKFTT 172 (TC), but they did not even consider that point.
Possibly the right decision, but not a terribly impressive judgment in my view. I note some criticism of the FTT judgment here too: