Yes it will be Cat C or D most likely.
No in the UK you dont need insurance
Be aware this is a dinghy
, used for short journeys, Its not a rugged RIB
. So use it for exploring in sheltered bays etc. Its not a long distance sea boat or anything like that. Stay close inshore, or use it on lakes or rivers where it will be fine
Ensure you wear lifejackets, get your self a waterproof hand held VHF radio
and ensure you tell someone your intended route
and return time. Avoid being on your own, on the coast , beware of tides, and return well within daylight. No heroics.
Consider doing the RYA powerboat level 2 certificate, very useful at this level
If you want to explore more coastline, a proper 5-7m RIB
is the thing.