Problem solved.
Turned off and unplugged fridge freezer.!!!!
Took grill off at bottom of freezer at front, ( two screws are visible when freezer door is open)
The cooling element was blocked with dust a pluff, I cleaned with duster and hoover, ( use duster to make sure all the element is free from dust) This element is cooled by a fan at the back of element, because air way was blocked it wasnt able to expel the hot air.
A simple solution to a frost free fridge freezer that wasnt getting cold enough.
May not be your problem but worth a look.
(ALWAYS UNPLUG FRIDGE !!!!)
Terry Seyforth, July 2005