Visited Manly twice, it stormed out and we did not even get to manly beach itself. However since we were already there, we decided to do the bush walk in our raincoats and umbrella. Great to know that we were not the only one on the track ... in the 2-3 hour walk, we only met 1 other crazy couple in raincoats.
Collins beach was nice and secluded, but no luck spotting the fairy pengiuns.
The "hanging swamp" along the Gunner's Walk trail from the former School of Artillery was actually very nice in the rain. It gave the swamp a very mystical feeling. The swamp is located where the rocks are less permeable to water, collecting rain water thus forming a swamp up in the highlands.