John,

Having bitten the bullet and had a look at the 1911 Census, we don't, in fact, have a connection.

From the Census, your Herbert Leslie Thompson was living at 99 Cartmell Road, Woodseats, Sheffield with his family:

- Henry Jamieson Thompson (Head), aged 33, Railway Engine Stoker, born in New Galloway, Scotland
- Mabel Chisholm Thompson (Wife), aged 34 (married 8 years), born in Mauldon, Beds
- Arthur Doglas Thompson (Son), aged 7, born in Sheffield
- Geoffrey Alan Thompson (Son), aged 4 born in Sheffield

Plus a correction to my family group - Norman Thompson doesn't seem to have been the son of Sidney, but was the son of Mary Jane Thompson (thus illegitimate), who was also living with her sister Emma Elizabeth at 38 Parsonage Crescent (district Ecclesall Bierlow) - the transcription incorrectly shows Emma as being Mary's daughter.

Regards,
Ian.