Hobby's have offered this plan, and the materials for building it, for many years. I first bought one of their catalogues for their dolls house bits 22 years ago, and this plan was in it but obviously far from new, then. Interestingly, the photo of this house in the current catalogue is a mirror image of yours, with the large rooms on the right and the hall to the left of the stairs. This is true for the catalogues I have going back to 2008 (I've not kept any earlier ones). It looks as though their stock photo has been reversed in the printing, unless the builder of this one decided to reverse it for their own reasons.
Oddly, Hobby's haven't offered internal doors for their 1:16 plans in the years I've been using them, and I suspect never have.
Oops!
Oops, you forgot something.