Looked at some more trails around Narrabeen. Too narrow and snakey and rocky as usual, so just headed around the lake which was much more pleasant. Two k at around 4:08 at 4:03 for a bit of effort.
Post run went to Collaroy pool, did two laps and my arms were dead - as was my Garmin which apparently is no longer waterproof. Guess I've got an excuse for getting the 620 now.