Hi Doug,
You will find Dart in the gutters pretty much all year round.
I have not got any good locations for you , I have caught 90% of mine on Fraser Island, but I would try any good looking gutter you can find.
As for bait I think pippys are best, collect about 20 big ones shell them, cut in half drown them in salt and leave in a bucket overnight so they really stink, the salt also makes them rubbery and they stay on the hook better.
Also I have caught heaps while targeting tailor with pilchards on gang hooks, and I have found if they are thick they dont mind having a go at slugs. I caught about 20 in two hours last year on Frazer Island while spinning for Tailor , one even swallowed the untire treble which is a good trick considering the size their mouths.
They can be fairly close to the beach also, when I was catching them on my tailor slug , if I got hit 40 or 50 metres out it was a tailor if I got hit 10 to 20 out it was nearly always a dart.