View: https://youtu.be/7erIBjX-epA
My sister and brother-in-law have bought this one, I'm dead against inflatables in the sea, but they say it is fantastic and nothing like the old ones at all.
The itiwit 3 is a fantastic inflatable kayak, solidly built and great value for money. The whole design is well thought out and the construction is really solid.
As you rightly say though, I really wouldn't be thinking of taking one too sea in the UK, unless it's a dead calm day and you have timed it perfectly for slack water and even then I really wouldn't recommend it. As can be see in the video thumbnail, the gunwhales are really high and as a consequence it's really susceptible to wind, along with a lot of rocker, meaning it handles like a cheap canoe more than a kayak. The width across the gunwhales is also quite large, so I struggle to get a good efficient paddle stroke in.
With taken the middle seat out of ours and whilst I do use my old sea kayak paddles, I do think it would be better suited to a good open canoe paddle. We use ours for messing around on lakes and the calm river by us.