Protect south facing rear garden with PIR, facing the sun ok?

[britishboy7]

Am looking for an external PIR for the rear garden and looking at the Visonic Tower 20 to go with my Powermax alarm, I'm assuming the PIR is mounting on the house looking out over the area to protect?
The garden is south facing so a lot of the day the PIR will be in direct sunlight, could this cause any issues?

Or would you mount the PIR at bottom of the garden (in a north facing position) looking up towards to house?
Many thanks in advance

 

[sparkymarka]

Detectors pick up better across the beams , bottom of the garden corner set at 90 degrees gives best coverage

 

[britishboy7]

Detectors pick up better across the beams , bottom of the garden corner set at 90 degrees gives best coverage

Thanks SparkyMarka

Theres only 1 real access point into the rear garden, 1 of the bottom corners (still got to come through conifers the other side of the fence and climb a 6ft fence, so the detector would be mounted in the corner access would probably come from, that wont be an issue?