Many thanks 'dobfam' and 'BumbleB' for the additional snippets. There does appear to have been a William and William junior as well as a Joseph and Joseph junior.
Although the Crowthers lived at Linthwaite in the Parish of Almondbury, it appears that they baptized their children at St James, Slaithwaite, which I understand (from Genuki) was in the parish of Huddersfield. Presumably this was for reasons of convenience as All Hallows, Almondbury, is some distance from Linthwaite. What puzzles me is that I have noticed that many of the Crowther Slaithwaite baptism entries also appear in the All Hallows records.
From a combination of my research and the information provided, I'm slowly becoming inclined to the view that Joseph Crowther the father of Jonathan was the same Joseph as previously lived at at Hole House, Linthwaite, and who was the father of Joseph (1721). That is, Joseph and family moved to Lockwood some time prior to 1737. I have no evidence that this happened, so, if anyone has evidence which confirms this, suggests otherwise, or casts doubt on this theory, I'd be pleased to have it.