My inner back door is covered in deep scratches and gouges (some up to
10mm deep) where the dog has scratched at the handle to open to door.The door is an external one, and cost quite a lot, so I'd like to have a go at filling it. Some of the damage is on the edge of a glazed panel, so is prone to being hit.
It is currently varnished, but I plan to paint it.
What would be the best filler to use?