I find winter is the best time to fish the canals if you dont mind the cold.
During the summer time there seems to be heaps of small fish around 20cm, But over winter not so much.
I normally bait fish the canals as ive never had much luck with spinners.
I use 6lb line with a huhu grub or worm below a 1oz sinker. If you cant get natural bait you can use the small pink srimps you can get from the supermarket.
If the current is strong and the bait is drifting into the side of the canal I use glow bugs and let them drift in the current using them a bit like a soft bait.