The ones I know that DON'T have a window seat are 4232, 4235, 4250, 4253, 4636, 4642, 4657. There are 21 on Deck 4 and 5 we still don't know about. Hope this helps you choosing a cabin
Unfortunately they have told you incorrectly. I have compiled a list of all the Deck 4 and 5 seaview cabins on Iona and there are quite a few that people have reported back have no window seat