Stop it, he won't be able to sleep at night now wondering whether the 7-8 mm difference in position will affect the sound. After all, with the speakers that far back, most of the soundwaves would be blocked by the door panel, whereas a more forward placement would allow for a more direct "line of sight" between the speaker cone, and the listener!
it's 9:40 pm in the UK, OP are you outside already ripping your doorpanels off? Isn't this forum fun!