Hi Margot
I have found these entries on the government census site
http://www.census.pro.gov.ukIt is a pay per view site so you will need to pay to see the actual image to get family relationships etc. and check the info in the index. It seems evident that they are all on the same page of the census but you will need to check that they are all the same family:
1901 in Cockerton (Durham)
Edith HOLLINGWORTH 2 b.Darlington Durham
Eliz HOLLINGWORTH 10 b.Elton Durham
Kate HOLLINGWORTH 29 b.Darlington Durham
Mary HOLLINGWORTH 7 b.Rodhurst Yorkshire
Wm HOLLINGWORTH 31 b.Smalley Derbyshire brick yard labourer
Note the difference in William's age (20 years out from what you have) - it needs checking.
This is the 1881 entry that I found:
Ashes Farm, Low Dinsdale, Durham
John HOLLINGWORTH head mar 63 wighman (ironworks) b.West Hallum Derby
Eliza wife 62 b.West Hallum Derby
James SHOLLON/SHOTTEN son in law mar 27 ag lab b.Morton Palms Durham
Mary A dau 26 b.Stanley Derby
John grandson 3 b.Fishing Locks? Derby
William HOLLINGWORTH son unm 30 lab (ironworks) b.Smalley Derbyshire
RG11/4890 folio 91 page 33
Best wishes
Casalguidi