Hi Grumpy,
The first thread is absolutely spot on. It describes exactly the same problem I have had with my mower and I expect that I will be able to swap these drive shafts over now. There is also a reference to a place where one can get Greenfield parts which could be extremely useful in the future, if not a little costly on carriage back to the UK!
Just for the record, I have found this mower to be an absolute delight, cuts through anything (albeit clearly at the expense of putting too much torque on the drive shaft) and exceptionally manoeuvrable with its unique forward/reverse pedal (again probably a bit much on the drive shaft).
And final comment - Deadly Dave's description of the lubricant spray he uses as "Possum Piss" absolutely cracked me up - brilliant!!
Many thanks Grumpy.