i had a couple in that area when i got my car but as stone chips drive me mad i dealt with them straight away.i dont know about the tale gate did you get your car from motorpoint as all therecars are all irish imports.
I once asked a freind of mine what causes stone chips on a bonnet of a car ?and hetold me thatI drivre to close to the car in front and told me to keep my distance. He saied that wayI will not get so many stones hitting the front of my car off the back wheels of the one in front.He may have being pulling my leg butI do thatnowand I dont seem to get half the stonechips i did before.
Might have something to do with the rake of the bonnet? I've never had stonechips on the bonnet of any Focus/Fiesta/Mondeo I've ever had but my last C-Max got peppered with chips (sounds tasty eh?) on the bonnet. Last time I have a black C-Max...!!!
Back to serious mode, not had chips on the rear or tailgate, perhaps these marks are from gravel bouncing over the car and hitting the rear?
Did have a couple on the front but like MJ, I too sort them out straight away.
I own a Black Ultima which is also peppered but with mine it's along the bottom front and rearkicked up by the wheels, the Ultima has a body kit, you can't get mudflaps for it which is really infuriating!!