According to my source 97 production MkVI were built all but 2 were originally ordered as Mk Is and 2 were originally ordered as MkVCs.The numbers are confusing because of overlap between different Mks.Two prototypes are mentioned Mkl R7120 and a MKVa X4942. I also have 920 production Mklls built including 8 conversions from MkIs. Spitfire 70 ,Flypast magazine special is my source.Spitfire Mark II were in production at Castle Bromwich June 1940 to July 1941, plus a laggard in October, Supermarine finished mark I production in February 1941, switching to mark V that month, Westland built 50 mark I June to December 1941. Castle Bromwich started mark V production in May 1941. Plenty of overlaps with it probable any early mark V fitted with mark II cowlings came from Castle Bromwich, next most probable source are the mark II to V conversions.
If you can see the serial number mark II were between P7280 and P8729, the original order was for 1,000. There were 921 mark II, Rolls Royce says it built 5 Merlin XII September 1939 to February 1940, then another 1,097 April 1940 to September 1941, total 1,102, the Ministry of Aircraft Production says 1,104 built, or about 20% more than the airframe production. It would appear the mark II was intended from the start to have a constant speed propeller.
If you count X4942 as a mark VI, built in January 1941, there were 100 mark VI, main production December 1941 to November 1942. The Merlin 47 was meant for the mark VI only, apart from prototypes there were 119 built at Derby December 1941 to March 1942, plus 1 more in July, a 20% reserve compared with airframes. As of end June 1944 the RAF reports it still had 61 mark VI, including 5 in the Mediterranean, from 99 production and 3 conversions to mark VI, which would imply no spare Merlin 47 for other marks. The Ministry of Aircraft Production reports there were no Merlin 47 engine stocks in Britain end June 1944, but 3 were repaired and another 2 under repair in July. While 2 Merlin 47 had been exported sometime since 1 January 1941.
The online Spitfire listings state mark Vc AR465 and AR466 built by Westland in May 1942 had Merlin 47, which does not seem correct, otherwise only mark VI had Merlin 47.
The Ministry starts reporting engine conversions in May 1944, as of 30 April 1944 there were no conversions from or to Merlin 47. There were III to 45 or 46, 45 to 46, 46 to 45 and 50 to 45 or 46. As of 27 January 1945 again no conversions involving Merlin 47.