If you wish to use both bedrooms, you should make sure you let Sebastian know in advance, as apparently booking "entire flat" of a 2-bedroom apartment isn't clear enough. We were only able to use one of the rooms we had paid for, as there were no sheets or towels in the 2nd room, and there was a pile of dirty laundry from the previous guests left on a chair in the kitchen.
Additionally if you have any issues during your stay, be aware that Sebastian won't reply to your messages until after you leave. We notified Sebastian of the above issues as soon as we discovered them, but it was almost a week before he responded to us. At that point he was rude and tried to make out the problem was our fault for not telling him we wanted both rooms (no apology for the dirty sheets either), and refused our request for a partial refund.