The original colour of my restoration project is Primrose. Can anyone please tell me how to achieve this colour using modern paints - preferably 2 pack? I am aware of the colour mix - White 83%, Chrome yellow 17%, Black-trace. Does anyone know if there is an alternative?

I would have thought that the place to start would be a paint supplier. The colour mix would be the same to achieve primrose, whatever the paint type. The second part of the 2 pack is just the catalysr and does not affect the final paint colour.
I would advise having a look back at some earlier post though as I seem to remember that there may be a danger of cracking if the two packs are used on panels that are rather flexible.