Have you tried all the parish baptisms? One of my husband's ancestors gave a different parish for his birth place - Marown, Malew and Onchan - Malew was the correct one - and his age never varied by 10 years in each return!

I am compiling a list of Lonan Skillicorns based on the 1851 census - I have all the details you have given but would appreciate any more Skillicorn informaion you turn up.