Not sure about the southside Nick, but on the northside:
Freshwater point
Dee Why point, and Dee Why headland (lookout at end of Molong St, take path)
Long Reef
North Narrabeen
Warriewood/Mona Vale headland park
I'm guessing Newport would also be good.
For a big picture, Edgecliffe Blvd (north end) on Collaroy Plateau might be good.
Edit: on the southside, there's that cliff path from Bondi to Maroubra? You might check Google satellite view.
I was going to go to the coast to have a look at it, but changed my mind just to look out of my Manly Vale house. It is a wild weather OK.I made it to the point at Freshwater at noon today.. it was wild! Gale force winds, horizontal rain and salt spray, large and choppy 4m waves.. too dangerous to approach the rock platform but the experience from the headland lookout was excitement enough. I left the cameras in the car. Could have done with an X-U (Typ 113)!
There was a guy at the lookout with a Nikon DSLR (looked D810 size) and long lens on a cheap-looking tripod. The camera and lens were wrapped in some sort of neoprene jacket but it looked like it was not up to the task. While I watched a gust blew camera and tripod over, luckily it landed on him while he was stooping and he managed to catch it before it hit the mud. His tripod didn't have a hook for what looked like a heavy camera bag sitting underneath.
It was difficult to stand still or walk in a straight line with the winds. Quite an experience.
If things calm down later today I'll go back for another look, around 3-4pm when the light might be better.