The TfW/LNR only fare only exists from Manchester, not from Stockport or Wilmslow. You can buy it from Manchester and then travel from Stockport or Wilmslow - there are no break of journey restrictions.
I think you're referring to the flexible tickets here. There are TFW/LNR/WMR only advance tickets on the same routes, which do ban break of journey.
from what I could see it isn't permitted on the super off peak but the normal off peak does allow break of journey
What can you see, exactly? According to
nre.co.uk, the restrictions for JN (the ticket code for the super off peak tickets) are:
Outward Travel
Not valid on trains timed to depart Manchester Piccadilly after 04:29 or before 10:30 and not between 16:00 to 19:00.
Not valid on trains timed to depart London Euston after 04:29 or before 10:30 and not between 16:00 to 19:00.
Return Travel
Not valid on trains timed to depart Manchester Piccadilly after 04:29 or before 10:30 and not between 16:00 to 19:00.
Not valid on trains timed to depart London Euston after 04:29 or before 10:30 and not between 16:00 to 19:00.
There is no reference to break of journey, and the ticket type permits break of journey. As such, you are allowed to buy a Manchester-London super off peak ticket and start your journey in Stockport or Wilmslow.