Spitfire markings
 

I hope this is the right place to ask this:
While at Duxford this weekend, the Boultbee Spitfire was doing some "trips around the bay". While watching it return to the parking area, I noticed that the aircraft carried the markings "KJ-(roundel)-I" on the right side of the fuselage. When the aircraft turned so the left hand side was closest to me, I saw the markings read "I-(roundel)-KJ".
I have seen photos on the web showing this aircraft with both the "I-KJ" and "KJ-I" on the left side.
Any clues what that is all about?
Kelvin

The 'KJ' is the squadron code and the 'I' is the aircraft's identity within the squadron.
The roundel has a specific position on the fuselage as the primary identifier of the aircraft - ie.. 'It's one of ours'.
The positioning of the lettering is secondary and placement was commonly according to the remaining space available on the fuselage.
Changes in policy at the time or other reasons could account for the reversal, also.

The chaps on the Military Aviation forum would be able to explain it better than I've done, I'm sure.
You might like to post your question on there.
They'll probably even be able to tell you what specific aircraft those codes represented at what time.

The Aviation History and Nostalgia forum is also a very good source of info on such matters.

Hope that's a start for you.
.

This book:

9781844156917: COMBAT CODES: A full explanation and listing of British, Commonwealth and Allied air force unit codes since 1938 - AbeBooks - Flintham, Vic: 1844156915

might be of interest...