There are a few more than that. As East Anglia includes Cambridgeshire and at least Essex beyond London, I'd be surprised if there aren't as many as ten. Basically Sound used to be in a lovely big old schoolhouse near Mulbarton; characterful and huge dem. room. Unfortunately, they moved west to No Man's Land.
You're certainly getting your money's worth here. Wonder when the virtual tour will start.
Around Norwich, and stretching over a large area, is Broadland; its council is one of the efficient ones and council tax is reasonable. Much of the City is under Norwich City Council and those villages/towns to the south are under South Norfolk Council. The northern coast might be a tourist trap and contain Chelsea on Sea, but the Broadland area is, i.m.o., equally interesting and more bucolic, with rivers and broads offering exc. waterways and with myriad walking/exploring opportunities.
Norwich is, I believe, the best and most extensive shopping area in the whole of East Anglia (and beyond). It is now possible, with the recent intro. of the Northern Distributor Road. to virtually circumnavigate Norwich and its environs, with the A47 dual carriageway covering the southern routes and villages.
King's Lynn (which is a bit of an ancient dump) was, as aforementioned, a chief port for the Hanseatic League in the later middle ages. I wonder which king gave his name to it and what 'Lynn' represents. Could Google it, I s'pose, but where would be the pleasure in that with so many Norfolk brethren on pfm? Quite pleasurably surprised, really.