[Chris Thomas]

Dick is correct. All 2nd TAF aircraft had a narrow yellow outer ring and a narrow white inner ring added to their upper wing roundels from 3 January 1945. They had a yellow outer ring added to the lower wing roundels at the same time. It took about a month to complete the work on all 2nd TAF's aircraft. So effectively all roundels on the aircaft were then 'C1'. This included 5 squadrons of Tempests at the time (3,56,80,274,486) and 2 more (33 & 222) before the end of the war.

Incidentally 'C1' is an unofficial nomenclature invented post-war by Bruce Robertson (I believe) and used in his ground-breaking book 'Aircraft Camouflage and Markings 1907 - 1954', which enthused a generation of aircraft modellers, myself included. The correct term for the roundels was 'National Marking III'.

Meanwhile, from 7 January 1945, all other RAF aircraft (with some exceptions such as SEAC) had their upper wing roundels modified by the addition of the narrow inner white ring; this roundels were known as National Marking IA. This would include Tempests of 501 Sqn, 56 OTU, R&D units etc, in the UK.

Now the plug! '2nd Tactical Airforce Volume 4', due out in February 2009, contains a chapter on camouflage and markings (as well as tactics, weapons, squadrons, and various other topics which could not be fitted into the earlier volumes).
CT