Indeed. That's the problem. I used to buy PIR lights from TLC & fit them for customers, thus earning a mark up on the product.
I've since found them so unreliable & problemaatic that I now tell the customer to buy them & I'll fit them. That way I don't get the warranty hassle.
If I could find a source of good quality PIR lights I'd revert back to the old system, but how can you tell?