The suspected cause of its early demise was that the 32mm nut securing the drive shaft to the hub became loose over time and the amount of play allowed movement in the bearing that should not have occurred. This accelerated the wear within the bearing unit itself.
A new hub and bearing unit has been installed and the drive shaft nut now has Loctite applied and retorqued to spec. A big thank you to @silas.andrianto for the heavy lifting and mechanical advice. Time to order a spare hub and bearing!
