If you look at the IGI on FamilySearch.org you will see 4 John Kinnish/Kennish entries for bapts in 1857 (this is before compulsory birth registration in the IOM).

JOHN JAMES KENNISH Christening: 20 APR 1857 Laxey, Isle Of Man, Father: JOHN KENNISH, Mother: ELIZABETH NELSON
This is an extracted entry - extracted from the parish register (as opposed to a Church member's entry which could be wrong).
There is a second entry for this bapt, under Lonan. (Laxey, Lonan.)

These are also extracted entries:
JOHN JAMES KINNISH Christening: 24 MAY 1857 Andreas, Isle Of Man, Father: THOMAS KINNISH, Mother: CATHERINE CHRISTIAN.

JOHN KINNISH Christening: 19 APR 1857 Lonan, Isle Of Man, Father: THOMAS KINNISH, Mother: MARGARET LOUISA QUAYLE.

This last one looks like the one previously found, but how did they know that one was right rather than the other two?

What other information do you have about John Kinnish so that he can be put into the correct family? Who did he marry, where and when? Children's names, dates, and places?
Did he emigrate? When? Where and when did he and his wife die/were buried?

Sue