is actually very close to the IWC Mark 11 except for that d@mn Luftwaffe triangle. You have to recall that the Mark 11 spec did not come out from the British MoD until
after the war in 1948. So historically, IWC did not create these watches Mark 11s for Spitfire pilots at all.
And the Mark 11 spec was fulfilled by both IWC and JLC. IWC kept making the Mark 11 from 1948 until 1981! JLC stopped making their Mark 11 in 1953 after completing a final order from the RAAF.
Another thing to note is that the IWC Mark 11 was made for the RAF, RAAF, BOAC, and civilians while the JLC Mark 11 was only made for the RAF and RAAF and not available to civilians at the time and much more rare than the IWC version.