Continuing research in Normandy shows that Sinclair was usually a title given to a man for exception service.
The title was given with land. Their is a lot of information now available, especially with the name "Sinclair D'Arcy".
The plot thickens... There appears have been quite a bit of German-Scots interaction. The two hander sword was
developed in Germany and taken to Scotland by an interaction by German mercenaries and Scots according
to French records. It then became the Claymore. The heaviness of the weapon would mean the footsoldier
could bring down a mounted man with a two metre blade simply by swinging it. The momentum would enable
him to dismount a knight in full armour. It was relatively inexpensive because a foot soldier only needed it as
his single piece of field equipment. The english on the other hand, employed Helvenic mercenaries.
Most of the information that I now have comes from the town of Sinclair D'Arcy.