Wonderful sleuthing, thanks!
I also got the will for William Chandler, husband of Margaret Bradley and executor of the will for James Sansum Chandler. He mentions a brother Christopher Chandler from Watledge in Gloucestershire and another brother John Chandler from Nailsworth, Gloucestershire. Nailsworth is the main town, Watledge is a small hamlet just down the road. Enoch Chandler, possible/probable father of James Sansum Chandler, was from Nailsworth and his son, Isaac Punter Chandler, lived in Watledge where he owned several cottages. William's will also mentions a sister, Eliza Earld of Nailsworth (to be honest I'm not sure I'm reading this correctly - see attached image, what do you think?)
I can only find one Christopher Chandler in Watledge. Married to Patience, he was born in nearby Horsley parish in 1817 to Mary Chandler (no father on the baptism).
A 1841 census entry in Nailsworth has Mary and her three sons, John, Christopher and William - it all looks to be a good match.
Possibly the same Mary and John also appear on a later census together, but I can't be 100% sure it's them.
There does seem to be a baptism for Eliza - Elizabeth Chandler, mother Mary Chandler (no father listed) baptised in Horsley in 1819. I can't find a clear record for her after this, though.
Other beneficiaries in the will are James Chandler (I think this must be James William Chandler, son of James Sansum Chandler), and Eliza Chandler, daugther of Esther Chandler.
It all sounds like William Chandler's family must have been closely related to James Sansum Chandler's family from Nailsworth / Watledge, but how exactly? It doesn't seem like William was Enoch's brother, but a 1st cousin maybe?
William was clearly from the Nailsworth area, so how and when did he get to Australia?