Obviously this is much much too late and I apologise to the max.
There appears to have been 4 Senior episodes and 6 Junior episodes.
It was probably just one off specials filmed that they split into episodes.
There was only one stage but it incorporated obstacles from the first 3 stages so it was difficult. The course was nearly identical for the Seniors and the Juniors, with the Seniors having a more angled spider walk and treadmill to contend with during the maths puzzle.
Heres the links to the TBS site of each where you can see the obstacles and click the tabs at the top to see how each competitor did.
