I have had to bog up the top half of the box and begin sanding it back. This has meant dragging out the table i got from work and getting myself set up outside.
I have split it into 3 parts - top, bottom and bottom flap. I am aiming to sand each down progessively through 80, 240, 400, 600 grit - when it is all down to 600 grit I will move on painting.