Interesting photo, sorta similar to what we use in the school here in Calgary and in the association. I would adjust a few things, 1) the defenders right hand, I would put it on the kickers right knee, Pak sao per say, 2) my step(in the photo the defenders left leg/foot) would be directly sideways, and a good 10-16" step, and the left hand would form Tan sao as backup protection. The key would be to contact and control the knee, which has to be raised up to kick someone in the upper gate, stop the knee you stop the kick, so you don't have to worry about his shin or foot.. When applied with the side step the effect is enormous on the person kicking, the rebound back is great and one would probably have to perform an entry tech or Pseudo entry (entry with front kick) familiar to the TWC people, to get the gap closed. Done properly this is very hard for the kicker to counter since most of his time would be spent on trying to regain their balance, while that is happening you would be closing the gap and attacking.

James