It's definitely not a bolt-action as far as I'm concerned because there's no bolt to pull, or being pulled.
The purpose of the 'bolt-action' as we know it is to provide manual control over the process of ejecting a spent casing and chambering a new one, which provides significantly higher accuracy as there isn't any jerking about going in the rear of the gun from an automatic/semi-auto action.
The Vectis, though, I see no casings ejected in use, so a bolt-action would be effectively just for show to open the chamber for loading (breech loading). But it appears to just pop up the rear portion like a lid when firing, so, again, no bolt to pull. The 'frame just inserts a round there and smacks it down.
The semi-automatic definition however is technically still correct if the Vectis is ejecting casings. A semi-automatic weapon by definition uses a system (such as recoil or gas from the fired round) to eject a spent casing and/or load a new one.
From my observations, -technically- the Vectis is a semi-auto in that it does automatically "open" the breech for the next round, but is also a bolt-action in that each round must be loaded individually, resulting in said auto-opening breech to be operated. Its really more of an "assisted breach" weapon than either term previously mentioned. And thats my 2 cents on the matter.