Very odd. I dont understand how it even compiles without generating a
"wrong number/type of parameters" error.

Once Im alone-ish, I'll have a look at the whole "tank_controls" action
and tidy/fine-tune it a bit.

Is is seriously different to what you posted about 8 post back?
The post where you posted a whole main.c file for testing.
(your post started with "No, it's not the level, and not the model.")