Can a Diplomacy player pick and choose which unit to support?
From the rules:


  A unit ordered to move can only be supported by a support order that matches the move the unit is trying to make.



The support order was: A Bur S English F Nrs - Bel
The move order was: A Yor - Bel (Possible because of F Nrs C A Yor - Bel)


There are two conflicts:
- The supported unit is a Fleet, the moved unit is an Army. This alone could have been a typo.
- The supported unit is the unit in Nrs, the moved unit is from Yor. And those are clearly two different units. There is no quesion that these do not match.

So the orders where conflicting, they should have failed.