I must be reading the IVA manual wrong. It seems to say pre-Aug 1986 was the CO<=4.5%, 1 Aug 1986 to 31 July 1992 CO<=3.5% and post 1 Aug 1992 CO<=0.2%/0.3%.
My Reg Certificate says my MX5 donor was first registered on 23/02/1995, which according to this post means I don't need a cat and CO<=4.5%, but from the IVA manual I need one and need to meet the 0.2/0.3%?!?
Am I being thick?