OnTriggerStay/Enter not working on instantiated objects

Hi,

I have been trying to solve this problem now for a few days with no results. I am creating a strategy game and when the player spawns a building, i want to check that the object has not been spawned within another object. I have tryed OnCollisionEnter/Stay and OnTriggerEnter/Stay but with no results. The script is atattched to the object which is spawned in, and yes i have is trigger checked on the collider. I also have a rigidbody attatched but have tryed it with and without a rigidbody. Here is my code:

 void OnTriggerStay(){
 
     Destroy(this.gameObject);
 
 }

Thanks in advance, Matt.