Hi Darren, sorry for the long delay in replying to your query..
I bought all the parts I needed new back in June 2016, some from my local Mower Shop - Ingleburn Mowers in Ingleburn and the half case from the USA.
Hydrogear Seal Kit (to suit 319-0500) 70312HG $65.00
Hydrogear Seal 4507HG $ 7.00
Hydrogear Bolt 44876HG $ 4.00
Hydro Gear Lower Housing 532142986 $120.00 - USA
Hydrogear Filter 532169893 $ 39.20
As for where I found them, I got the part numbers from the PDF File images I posted in my original post and went to my local mower shop. They got them in for me.
