Hi Vicki,
The christenings of those children are on the IGI (familysearch.org) and it looks as though they are extracted from the Parish Record. Therefore, I would say they are fairly reliable. However, you can order the film (Source call 0919765) for St. Martins and view it yourself at your local LDS Family History Center. There are centers all over the world and you can find them listed on the familysearch web site.
Hope this helps,
India