It is exceptional for my wife and I to return to the same restaurant twice when we are on vacation. The pub's lamb burger is heaven, the beer divine, its claim to being the oldest pub in Sydney unverifiable--2 others make the same claim--but the claim to best beer, I have no doubt!
You can't make reservations that I know of but perhaps if you're a guest at the hotel you may. We were there only for the food and beer. You walk in and hope to find a seat or, stand and drink if you're not having food.
We ran into a couple English expats living in Sydney who said this bar is their favorite English style pub. I can see why.