Sorry, not got an answer but I know how you feel. I've got a slight scratch in the light grey plastic door surround / bezel of our Dometic CRX50 fridge - it's barely visible but I know it's there. I tried giving the out of sight inside edge a rub down with a fine grit wet & dry but found that although it would get rid of the scratch, it would also put a sheen on the surface which would show more than the original scratch in the right light. I'm now tuning it out every time I go to the fridge.
best and safest way I have found , is to buy permanent marker pens in the same colour (or slightly darker) as the plastics....
I have 2 different greys, 1 for the dark grey on the dash board and 1 for the lighter colour on the doors.
carefully follow scratch with marker, then rub in (off) with fingers. Repeat till happy with result.
Works for me...hope it works for you.........stay well everyone.