Anyone advise the correct seal to replace for the reservoir in the 638082-A hydraulic power pack assembly?

Been having extended pump running on power up and eventually found the seal between the reservoir and the pump protruding and oil leaking out as the pump ran.

Been trying to chase up the correct replacement seal here in Melbourne (Aus), but having the devil’s own job trying to find the correct seal.

Cheers

Dom Crain

VH-CZJ