I'm looking for Henry (b1816) & ELizabeth Sheppard(b1818) and have found them in all the censuses bar one!

To start with, I thought the family had moved from Norton St Philip in Somerset, because they weren't on the 1881 census. Then I found they were definitely there in december 1880.

Browsing through the images in Ancestry, it looks to me like some pages have got missed off the end as Norton Farm, Wick Farm, Wick Farm Cottages, New Lodge etc, together with their resident families are all missing.
Anyone got any ideas as to how to find out whether they are genuinely missing, didn't get filmed or what?
All suggestions welcomed....
Thanks
Angela