That's a 1uF Capacitor 500V. The equivalent is part number "104Z 500V". Jaycar should stock it, but their web search function is horrible.
Might be worth waiting for someone else to chime in, but I'm sure I used these caps on my JP that was missing the cap.
Its a 0.1uF 500v ceramic cap. Jaycar dont have ceramics in anything bigger than 50 volt rating (not sure if the 500 volt rating is needed here or not).
They have 0.1uF 630 volt polyester cap that could probably be used without any problems.. link below;
http://search.jaycar.com.au/search?w=rg5210&view=list
