Hi Glenys,
Corrin is a Manx name so he (and his parents) could have a reason to return to the IOM.
As you have the birth certificates, you should have the names of the parents and possibly locate them on the 1881 census. I did not find Sarah or Robert in the 1901 online census but as it is riddled with transcription errors, there could be a misspelling.
Do you know where the three daughters were born?
If so try www.1837online.com
It is a pay as you go but has all post 1837 births in alphabetical order by quarter.
Bruce