There's one normally held at Great Blakenham near Ipswich in Suffolk during September every year, and I think there used to be another there early on in the year.
Also at the much larger 'Copdock Show' held at the Ipswich Showground in early October.
The 'Fenman Show' held at Wimbotsham village in Norfolk on August bank holiday Monday each year is the only regular event in Norfolk that I can think of.
And the BMF Show in Peterborough in May held at the Peterborough Showground,
