UPVC doors move a lot in heat extremes and you may experience difficulty locking the door. DO NOT FORCE THE HANDLE UP!! The locking mechanism is fragile and may well break.
If you intend to leave windows open at night (or even in the day) consider fitting window restraints to prevent any unwanted intruders climbing in! For upper floor windows it will also help keep youngsters safe.
When out in the garden make sure any exterior doors you can’t see are locked – opportunists just love summer!
Oh yes and drink lots