There will be plenty more Mick, hope the cleaner sorts the doors our for you.
I find the cause of this sometimes tends to be the "cockpit shine" stuff that is sold in Hlafords.
Whilst it can put a shine on interior trim, it should be applied by spraying the cloth first. If it is sprayed onto the door cards, where it first hits the plastic, it can leave the small shiny areas and blotches that you describe.
Always best to just use a damp cloth on the interior plastics, or any spray on stuff applied to a cloth first in my opinion.
Chris.