Welcome to the Norfolk master race* (NFN). We're definitely luck for sites. I'd recommend CAG but my new favourite is Battlestations!
Hoopers is alright. The owner is good (though the other staff are a bit grumpy) and there's some good stuff but it's quite expensive (even with 10% off). Beckets on Dereham road is also decent but with a smaller supply of surplus - more camping stuff. There's a surplus store on the market that's cheap - good for uniforms, everything else is Kombat gear.
*I'm not actually originally from Norfolk so I'm a dirty foreigner!