Its a side slip - the boat is floated on to supports and then winched up a steep incline.
They do a full range of shipyard work there - they were blacking a boat when I was there.
I was amazed at the amount of equipment lying around - in the UK, it would all get pinched.
750 Euro could be about right in the Netherlands assuming you are talking about a 15-25m boat - its dearer than the UK I find.
ETA I don't know if they will cut out and replace plating - there is a lot of residential boats and apartments around, not to mention a very nice bar opposite that serves Duval and takes international credit cards (quite unusual in Holland).