Public Liability Insurance

Direct Line came up as vastly cheaper than everyone else when I searched for my mums public liability insurance for her business. Granted its a small home based business, and different risks to your business, but worth a couple of minutes entering your details to see. They don't appear on comparison websites so you have to go directly to them.
you may also get a discount if you or anyone at your address has another policy with them - home, car, pet etc. or when you come to renew anything, a PL policy counts towards the discount

Try trade groups such as magic circle etc, membership often includes liability