Your Sir Russell scoffed at your landlors assertions and you seem to have interpreted the local dialect as hillis.
There is however a grain of truth in your landlords tale.
Clan MacKerrell The name, which means 'son of Fearghal', is documented in the twelfth century. Sir John Makirel fought at the Battle of Otterburn in 1388, capturing the brother of Sir Harry Percy (Hotspur). Sir John's descendant, Martin McKerrell, is described as 'in Hillhouse' at the end of the fifteenth century. Among others in Ayrshire, the estate was formally confirmed to William MacKerrell, 1st Laird of Hillhouse, by James VI in 1589