Our photographer actually suggested our ceremony location at Killalea - as coming from northern suburbs I had never heard of it or been there.
We booked Jamberoo Rec Park, based on the fact we could also have our ceremony at the same spot, as that was what we originally wanted to make things easier for our guests. However our photographer pointed out that the park does not close until 5pm and as we would have our reception say 4pm, there would be a lot of background noise and kids screaming and did we really want to deal with that? So hence why we changed.
It also works out great for my photos as I can have beach photos being at killalea and then get the country style jamberoo ones on the way back to the reception, best of both worlds (once again, thanks to my photographer for his suggestions!)