Hi,
You don't HAVE to have any.
I would get insurance as if you hit someone else's boat, or struck a swimmer you could be in a world of trouble. It is a small expense compared to what yo must have paid for your boat.
A RYA level two only takes two days, I did mine at Sunderland Marina. This is referred to sometimes as a boat ldriving license, and whilst not mandatory is very useful.
It means when abroad you can hire a boat. Plus more and more slipways are saying you must have tha level two and insurance before you can launch. In North Wales ALL council owned slipways demand both.
The course is a good way to meet local boat users and see how they do things.
Hope you enjoy your boat,
Geoff