Yes, sounds viable. I have only actually targeted flathead an a few occasions over the years. To be honest, I don't know if they are considered winter fish.
Bream are often considered winter fish and I do target them often. Frankly, I have not noticed a significant difference between summer and winter. But some people say bream are winter only...Flathead are often a bi-catch when fishing for bream.
One thing I do know is that a bit of fresh can bring the flathead on. It might not be a lot of rain, but it might be worth a try next week. I leave Nowra to head back out west in a couple of days, so I wont get to test it...But we look forward to seeing your pics. Good luck and let us know how you get on
itsaboat mate...Life is just a boat and then ya marry one !