exhaust emishions prof of engine age

[mabautouk]

hi has any one had problems when sending car for an iva test and not being able to produce log book ect from a donor vehicle that the engine came from as im using various donor vehicles to build mine i was wondering how do i get around the emishions test with my engine as there is no prof on its age it is a c20xe vauhall engine that was from a pre cat test calibra but i have no prof of that any ideas
thanks mark