I've sailed RC boats on the Broads many times, but usually from a cruiser or day boat rather than from shore.
Most of the Broads themselves are fine, LOTS of water of course, Barton Broad and Horsey Mere being to of my faves, but I've sailed on Wroxham Broad a a few times when they don't have sailing regattas going. Oulton Board is probably not a good idea as it gets quite rough from observation, but I have sailed there inside the Yacht Station area.
I'm not too sure about running fast electrics though, and with your ID here that may be what you'd want to do? My stuff was anything BUT fast.