Mine had a short cable from the bottom right lever and a long one from the bottom right that loops back up over the top of the control box to come to the controls from the left hand side (if looking at it head on).
My defrost flap is controlled by an actuator so not sure what cable this should have.
Mine is a later SA set up though so although the heater box is the same, the controls are different (knobs instead of levers and an extra flap that closes the outside air supply)
The cables have clips that anchor them at the heater box so that there is something to push/pull against when operating.
You might be able to adapt brake/gear cables from a push bike to do the job but it could get complicated. Worth trying some breakers to see if you can get a set of complete cables from them. Make sure you get the anchor clips also, my cables wouldn't work without them.
I also used a needle and syringe to inject some oil into the cable sleeve to try to lubricate them as much as possible. If the cables have been bent even slightly they are very hard to get moving.
