Ok here's another version.
On 2 Oct 1969 the first Nimrod MR1 (XV230) was delivered to the Maritime Operational Training Unit (MOTU) at St Mawgan in order to train Nimrod crews.
On 1 July 1970, 236 Operational Conversion Unit (OCU) was reformed by renaming the Maritime Operational Training Unit (MOTU).
On the introduction of Nimrod MR2 the OCU closed at St Mawgan on 1 April 1982 but reformed at Kinloss as the MR2 OCU, joining the Nimrod Conversion Flight which had been operating at KInloss since October 1979.
1 November 1983 saw a return of the OCU to St Mawgan.
The start of the return to Kinloss took place on 31 Jul 1992 prior to the cessation of Nimrod flying operations at St Mawgan.
With the disbandment on No 42 Squadron on 1 October 1992, 236 OCU was renamed Nimrod Operational Conversion Unit (OCU), No 42 (Reserve) Squadron.
During 1997 the Nimrod OCU, No 42 [R] Squadron was renamed to just No 42 (Reserve) Squadron.
From the 1 Jul 1970 to 30 Sep 1992, 236 OCU had the Shadow/Reserve Squadron designation of No 38 (R) Squadron.
Other OCU info:
In 1975 the OCU was awarded the Wilkinson Battle of Britain Memorial Sword for Tactics for its valuable contribution towards the development of operational tactics.
The OCU won the Aird Whyte Trophy in 1984, 1986 and 1989 and as 42(R) in 1993, 2000, 2002 and 2008.