Thanks xlnt for providing that extra information, it makes things a whole lot clearer. I'm not a carpenter, but as I see it the major problem with replacement of the settee for carpenter, apart from the cost, would be that moulded back rest. The seat basically consists of a "nicely finished" wooden box with rounded corners for the base unit, not too difficult to fabricate, and with a decent foam filled cushion on top, very easy for a reupholsterer to fabricate. Do you need a backrest? Only you can decide, but a number of 37s some years ago did not have back rests fitted to that item where it was only for sitting on while eating a meal, not somewhere to get too comfortable and stay there long into the evening while looking after a glass of something special !!
Perhaps on account of the costs in Norway, you could make up a specification for what you wanted, along with Yngmar's photo and ask for a carpenter in one of the nearby countries to make what you want, and give you a price, and then there is an excuse to sail over to pick it up !