I was at Warkworth Castle this weekend and thought I'd post to your forum in case you've not followed this line.
A noble Norman family acquired the manors of Warkworth, Clavering and Evre in the 1100's. Warkworth is in Northumberland, Clavering is in Essex and Evre is in Buckinghamshire. At this time they didn't have proper surnames, and attached their father's name to define them. In the 1200's the family split up 3 ways. The eldest, Roger fitz John inherited the three estates but the younger brothers Robert and Hugo got property which had come from their mother by marriage and went to live in Stokesly, North Yorks and Isle of Axholme, Lincolnshire. They took the surname d'Evre. Roger Fitz John was made a baron and became known as de Clavering and this became permanent. The de was eventually dropped. In my case it seems Evre mutated into other forms such as Evers and Vevers.
I'm not sure where the main Claverings lived. I guess they split their time between the three properties. I know that the Claverings were in Evre, nowadays Iver at least to the mid 1300's
Although Warkworth was eventually handed over to Lord Percy, Duke of Northumberland, I'm presuming that some of the present Clavering family descended from this line. Others may have resulted from those living at Evre, though this was I think eventually lost to the Neville family.
There's some of what I've found out at www.vevers.me.uk, though it mostly relates to my Evre line.
A quite famous Clavering is buried in Park St Cemetery, Calcutta.