Thanks Brian, your first census transcript in Port-e-Vullyn looks like the family I thought most likely:
Dorothy Corkill daur of Robert Corkill & Cath Kermeen bapt Maughold 20 Aug 1843.

Robt CORKILL aged 47, Port y Vullin, was buried Maughold 4 Apr 1853.

I think this is probably Robert son of William Corkill & Elinor Christian bapt. 14 Sep 1806. [William Corkill & Elinor Christian married in Maughold 16 Dec 1802.]

Mother Cath Kermeen would be Catharine daur of John Kermeen & Jane Corkill bapt Maughold 19 Jun 1814. [John Kermeen & Jane Corkill married in Maughold 18 Dec 1824.]

In the 1861 Maughold census Catherine was recorded as:
1 102 Port E Vullin Catherine CORKILL Head WID 47 Labourer Maughold
1 102 Port E Vullin Judith CORKILL Daughter UNM 24 Labourer Maughold
1 102 Port E Vullin Elizabeth CORKILL Daughter UNM 9 Scholar Maughold.

No sign of Dorothy in 1861 in Maughold.

Sue