Not sure you will be able to repair it as it is a plastic laminate glued to plywood and once the 1mm thick top laminate is broken all you can do is fill it with a matching filler.
You can buy a similar product, either just the 1mm laminate or laminated to plywood from here robbins.co.uk/our-products/marine/marine-plywood-panels/ although probably not a lot of help if you are in Greece.