As mentioned, yes to VA lounge at SYD Domestic terminal. Also get to use the VIP entrance with their own security lanes...after being dropped off from transfer shuttle, go past the main entrance doors (with the flow of traffic), up the ramp to the VIP entrance that drops you right into lounge with brekky and showers.

Only challenge you may have, as I've had twice a year for the past 6 years is return baggage. VA is supposed to give you DL baggage rules on the return, but usually had to be explained to them..helps to have printout of Delta's baggage page.