As per others already and Morgan and Shacklady. Griffon Spitfire proposal in November 1939, little done for a while then the contract for two prototype mark IV placed on 26 May 1941, though the mark number had been reserved earlier, the first Spitfire V was around in January 1941. Mark IV DP845 maiden flight 27 November 1941, second prototype DP851 the next month. Ultimately DP841 was the mark XII prototype, DP851 the mark 20 prototype.
Griffon II production began in April 1942, Griffon 65 in December 1942 but by the end of 1943 only 74 Griffon 61, 65, 71 and 75 production engines had been built, including 35 in December 1943.
Merlin 100 series to end 1945, 16 Merlin 100, 2 Merlin 101, 7 Merlin 102, 102 Merlin 104 (100 in August/September 1945), main production versions Merlin 113 from August 1944, Merlin 114 from October, Merlin 130 from January 1945, Merlin 131 from June. There were 164 production Merlin 100 series engines built in 1944, so while production began nearly 2 years after the two stage Griffon, "mass" production was under a year behind.
Michael Bowyer in British Interceptor Fighters reports the Merlin 65 was type tested in mid 1942 at 2,300 HP at 500 feet and 2,060 HP at 15,750 feet. First production Spitfire XII in October 1942, first production mark XIV in October 1943. Bowyer notes the Merlin 65 was two months too late but by mid 1942 the Griffon was the allocated engine for the Spitfire, the war situation and the capacity of the British economy meant the decision was effectively locked in.
Merlin 85 production from January 1944 to June 1945, 1,420 built plus 14 Merlin 85T, the engines were reported to have enough problems the RAAF substituted Merlin 60 series engines on its Lincolns.