Yes, I see.. I looked at a bunch of other RAF skins (I should have before posting

)
I see that the RAF markings differ to the Luftwaffe's.
RAF keep their codes in the front or rear of the roundel on both sides of their aircraft, while the Luftwaffe keeps their markings in order, ie.. O+JX would read O+JX on the other side.
I learned something today, thanks.