The FamilySearch catalog at https://familysearch.org/search/collection/list is the way to find out of a particular collection is available. Here's the list for the censuses of England and Wales.
They're all available, from 1841 to 1911. FamilySearch just updated the 1901 collection as highlighted by the asterisk against the date under Last Updated.
The other icon shown is the camera, in two styles with, or in the case of 1871 without, a black frame background. Do you know the difference?
The answer is at the FamilySearch Blog in a post from May this year.
"When an image of the original record is on FamilySearch.org, you see a small camera icon. When the image is on a different website, there is a small web page box behind the camera."