If that Nov.1869 baptism for Emma Catherine Cowle was the right one her age was wrong in the 1881 census, unless it was a late bapt. In April 1881 she should have been only about 11.
But assuming it is correct, the LDS film showing her bapt is FHL BRITISH Film 106187 Item 1. Christening, marriages, burials 1868-1883.

There are bapts for other children of William Cowell & Catherine at the same church:
IGI has:
STANLEY COWLE Christening: 10 JAN 1864 Saint Barnabas, Douglas
JOHN COWELL Christening: 19 JUL 1855 Saint Barnabas, Douglas
CHARLOTTE ANN COWLE Christening: 05 NOV 1871 Saint Barnabas, Douglas
ROBERT COWELL Christening: 07 NOV 1852 Saint Barnabas, Douglas

Sue