Unless the cupra's different to the FR - you won't have a button in the footwell - the interior sensors are disabled by pressing the lock button twice
Also don't one click the car with a person in it, misses had the shock of her life when she was sat there just breathing and the car alarm went off, I had a look on me face of... what did you do?
I believe that the internal sensors are location within the lighting console, and also there are is something intergrated into the top part of the door frame.
Also it auto locks after you hit around 10mph.
Oh and tell your passengers that they need to pull the internal door handle TWICE to get out, or your mate will be giving it back to you with a "sorry I've just wrenched your door handle off"
Why does yours not do/have these options?