Thanks for all the help.
I contacted Corgiwerx and got myself a refurbished Viscous Coupling. They were very easy to deal with and I would recommend them.
Brought it to an honest mechanic who fitted it for under $250 including oil. A far cry from the ripoff artist in Blackheath who quoted $1400 and then went on to say that a gearbox with 180000kms needs new bearings throughout and quoted $2400!!!
I took it to my daughters place in Rylstone and all is good, so very happy.
Thanks,
Pete