Public and Employers Liability Insurance will be down to you if you or one of your employees operate. Equipment also down to you but check with current insurer as this may already be covered. If not you can either insure by the day or take out insurance with the provider.
Not worth doing if you're not IPAF, just too risky all ways you look at it.
Lots of places hire out kit with operator but be sure you are clear what you're getting for your money. In this instance they should provide all insurances but it's still going to be your responsibility to make sure all is in order, as well as gain authorisation for subbing this part of the work.
Not enough info to help more, height, timescales, site layout / access etc.
Best call a local branch of these guys and seek their advice. They'll come walk the job with you and help you decide what's required and thus wghat cost is involved.
http://www.afi-uplift.co.uk/pressrelease.asp?pressid=46