Ah yes Norm, but of the problem at hand? ;-)

Not to worry I've ordered some of this from SCA:
https://www.supercheapauto.com.au/p...5kg/SPO3952440.html?gtmfrompage=checkout

Penrite specify it for gearboxes and also for ones that leak, if nothing else I figure it will stem the flow of gear oil, can't imagine it would do any worse than gear oil as isn't an overly intensive usage in a deutscher's gearbox. Seems a low risk way to solve an issue that would be an utter PITA changing the seals.