Bob, this is becoming a very profitable conversation, I think a information swap is in order, though you have supplied much more than I can offer. Here are the few facts I have about Leonard Hodgkinson, which I culled long ago from a 1912 edition of the local paper the 'Staffordshire Sentinel', you might find them of interest.
According to the article, Leonard was born at 20 North Street, Stoke (the road still exists, as do a few old houses, but the site of No. 20 and neighbouring properties is now occupied by a social club).He was apparently the fifth child and second son of John and Catherine Hodgkinson , so I suppose there must be two older children missing from the 1881 census return. Educated at St Thomas' School, Stoke, Leonard started his apprenticeship on leaving and his career developed as you have mentioned. The article ended by mentioning that there were several relatives of his still living in the Potteries, his mother was resident in Shelton Old Road, Stoke, while his younger brother Lawrence lived in Seaford Street, Stoke and worked at Sherratts outfitters in Piccadilly, Hanley. The latter seems to have been the source of this information, so I should imagine it is pretty accurate.
You mention the 1881 census return for Knowle Street ('Knowl' seems to have been a mistake by whoever compiled the return). That street also still exists, it adjoins North Street, but I have not yet been down to have a look at it to see if no. 5 still exists.
One nice fact I have always liked in connection with Leonard Hodgkinson, was that the Hartley and Co works were later taken over by Messrs Kerr, Stuart & Co, locomotive engineers. In the 1920's they had another local young man as an apprentice named Reginald Mitchell, who later went on to design the Supermarine Spitfire fighter plane. Perhaps they trained on the same premises?
I hope this is of some interest.
All the best