That was quick work, Donna, possibly identifying Mary Caine b.Lezayre!

If someone going to the MM would kindly have a look at the two marriages for you:
John Kermeen & Mary Cain married 30 Nov.1858 Ramsey, and
John Sayle & Mary Kermeen married 13 JUL 1865 Andreas, the fathers and occupations should confirm whether or not she was the same person.

I had looked at Mary A Kermeen aged 11 with the Sayle family in Andreas in the 1871 census, but was put off when both Mary A and Mary's places of birth were given as Andreas.
However, you found that in 1881 Mary gave her birthplace as Lezayre.

This is what I was able to add [in brackets] to what you wrote:
1871 Index [at 5 Ballavoddan]
Andreas 4 19
Sayle
John 39 b Andreas
Mary 34 b Andreas [b.c.1837?]
John 5 b Andreas [John James Sayle bapt 1 OCT 1865 Andreas s/o John Sayle & Mary Keneen (as shown on IGI)].
George 3 b Andreas [was actually bapt in Bride]
Martha 2 b Andreas
Mary A Kermeen 11 b.Andreas [actually bapt Maughold?]

1881 Andreas
03,05,023,SAYLE, John,B'Cross,Head,Married,50,Farmer 28 Acs,Andreas,Andreas [died before 1891]
03,05,023,SAYLE, Mary,B'Cross,Wife,Married,45,Farmers Wife,Lezayre,Andreas b.c.1836
03,05,023,SAYLE, George,B'Cross,Son,,11,Farmers Son,Andreas,Andreas [was actually bapt in Bride]
03,05,023,SAYLE, Horatio,B'Cross,Son,,4,,Andreas,Andreas [can't find his bapt.]

I also found:
IGI extracted entries:
MARTHA SUSANNAH SAYLE Christening: 18 APR 1869 Andreas Father: JOHN SAYLE Mother: MARY CAINE
WILFRED CAESAR SAYLE Christening:16 APR 1871 Andreas, Death: 22 JUN 1875 Father: JOHN SAYLE Mother:MARY CAINE
FLORENCE MILNER SAYLE Christening: 18 AUG 1872 Andreas, Death: 15 JUN 1875 Father: JOHN SAYLE Mother:MARY CAIN
IDA BLANCHE SAYLE Christening:13 DEC 1875 Andreas, Death: 12 MAR 1876 Father:JOHN SAYLE Mother: MARY MARGARET CAIN [Mary who married John Kermeen was Mary Ann Cain at her daughter's baptism.]
GEORGE JOSEPH SAYLE Christening: 30 JUN 1867 Bride Father: JOHN SAYLE Mother: MARY CAINE
Can't find Horatio.

1891 census Lezayre, Ash Croft:
Mary Sayle Head wid living on own means 56 b.Lezayre
George Sayle son S 21 employed b.Bride
Horatio Sayle son S 14 b.Andreas

In 1901 Mary Sayle is on her own in Douglas wid, 66, living on own means b.Andreas? Living at 8 Chester St. Speaks both Manx & English.

I couldn't find Mary Ann Kermeen after 1871 unless she married John Kinrade aged 32 b.IOM and was living in Lindal, Dalton In Furness, Lancs in the 1881 census, with John T. KINRADE Son 3 m b.Dalton, Lancs.

Or this could be her burial:
KERMEEN, Mary Anne 16 And 5 Apr 1876.

Sue