The Crosse family, a name also strongly linked with Peel Garrison were in possession in 1515 - I guess I should look at Patrick records as Knockaloe seemed strongly linked to the Garrison (it contained I think the Lord's rabbit warren - an important source of fresh meat) - but as you say the Radcliffes (or Ratcliffes) were almost certainly a Stanley Client family - most of such families were from South-west Lancashire though there were some outlying Stanley estates.
Some of the later Kockaloe family history is at http://www.isle-of-man.com/manxnotebook/famhist/families/awm1889/notes_rd.htm