I'd try adding some zylkene to his food too, and using pet remedy spray on some of the furnishings, especially if you've replaced any with new. He will be feeling like the house is not his old familiar territory and needs help to adjust to his new surroundings. Scent is one of the most important ways to do that, and having their bedding, toys, cat trees or scratching posts etc from their old home will be a comfort. So will items of clothing of yours left in the new rooms, so they dont smell so strange.
Food and play are the other two really useful ways of settling a cat into new surroundings.
Sounds like your move to the cottage has gone well, otherwise. You must be so pleased to have made the move.
Here's wishing you everything you hope for and more in your new home.