I always have this predicament. I live in Manchester and as someone once said "here's a message for all shipping in the Manchester area, bugger off, there's no water". Try looking at www.boatlaunch.co.uk
. I would use it to look at where they are & if you can launch. Beware, councils change slipway procedures sometimes, so I'd be careful about the information it gives you. Always call the controlling authority to find out if they have any registration scheme or limitations. If you find anywhere good that isn't listed, any chance of an e-mail?