Freelance and self employed insurance help

[JABB]

I have set up a company to help people move, downsize and sort through after someone has died, sending items to recycle, ebay or local auction.
As well as this, I want to do voluntary and freelance work for museums and national trust style homes.
One museum has already asked for Freelance insurance and I have looked at PL. The trouble is, I don't fit the form pigeon holes.
Can anyone advise please?