I have to carry PLI for my work as a freelance stage lighting technician and most of my colleagues use one of three insurance brokers in the UK who specialise in entertainments...
Robertson Taylor in London
Torribles in Bristol and Exeter
Arthur Doodsons in Manchester (can't find a website, but try +44 (0)161 225 9060)
I get mine from Torribles and it costs about £350 a year... and that doesn't include waving fire around. I went there from Robertson Taylor, who had become too expensive, because the "all-in" package they offered was too inflexible; Torribles were able to break things up into smaller, more affordable "items". In the end you will probably wind up paying the same price one way or another, wherever you go, because the above companies are just brokers who put packages together; the actual policy terms and premiums are dictated by some names at Lloyds.
Be aware that having PLI is only half the story and it is far from being a Get Out Of Jail Free card. If the unthinkable happens, somebody makes a claim and the insurers decide you've broken any H&S rules or conditions of the policy, they may sue you back for any payouts
And if you're going to get £2,000,000 of cover (which most events organisers and suppliers insist on as an absolute minimum), you might as well get £5,000,000 - it won't actually cost that much more
