My malfunctioning Prestige PRT295FFCS 16 month old fridge freezer?

My fridge section's flickering light shows E1? the fridge is icing up, especially the 3 veg drawers, freezing the contents? The freezer section is working normally at -18.
The back of the fridge shows ice building up! any suggestions, I'm fairly handy with tools. I do not wish to replace it as it's less than 18 months old. Any advice would be gratefully recieived