Nice shed.
Pity for it to rot because you saved 6pence on 'paint'.
Treat it to the best you can find.
If all else fails, and no-one has a spot-on recommendation,
just check the Toolstation catalogue.
I have used bedec "barn paint" on my timber board clad house for a few years. That stuff is great, you can get a decent paint supplier to mix it any colour you like
I need to paint my shed that I built over the summer https://www.lfgss.com/comments/14750759/
Whats the LFGSS approved exterior primer and exterior wood paint? Ideally on the 'economical' end of the price range.