There are over 1,300 County Wildlife Sites (CWS) in Norfolk. They support a wide range of biodiversity, including many priority habitats and species identified by the UK Biodiversity Action Plan. Together with Sites of Special Scientific Interest (SSSIs), they are the most important areas for wildlife in the county. See here for more information. Those in South Norfolk are listed: CWS in South Norfolk.
Of these three are in Wreningham: Ref 65 – Flordon Meadow (West); Ref 66: Wreningham Hall Meadow; Red 67: Wreningham Meadow. The 1985 survey information is here. The 2016 survey descriptions are:
65 CWS Flordon meadow (west) 2016 survey
66 CWS Wreningham Marsh 2016 Survey
67 CWS Wreningham meadow 2016 survey