Recommendations for Public Liability Insurance?

I am doing a short job (four days) filming corporate work plus editing. I have been asked to provide public liability insurance. I usually just work in production so this is not something I usually need or to be honest know much about.

I wondered if anyone had any suggestions for insurance companies? I also wondered do I need something TV specific? I am not a member of any trade organisations (Directors UK/BECTU)

Thanks,
Will