I have spent all day trying to find ancestors whose dates of birth marriage and address are known to me in 1901 and cannot access them in 1911. What am I doning wrong. I have tried entering the GR nos from 1901 without success also.

Where are you searching the 1911 census?
From my experience the 1911 census on brightsolid is riddled with spelling mistakes which make searching difficult. Try searching for an address instead of a name.

The reference numbers used in 1901 have no bearing whatsoever on the ones they used in 1911.

Carol

try just searching for the first name or second name (not both at the same time) an area and a bith date with a couple of years either side. fiddle around in this way and if you still cant find them then concider that they died ,moved or emigrated or did not takepart in the census. i spent a couple of hours looking for my greatgrandfather jesse ruffles b 1850 living in brixton from bacton only to find that he had been transcribed as george raffel born 1849 so a little bit of hunting and latral thinking and you might find them.