
Hi, dont know if your friend has thought of it but I do a stall at various events and some organisers want to see a copy of insurance before they will accept booking, mainly 3rd party in case someone falls over your table or if your gazebo thing falls on them, very few if any will cover stalls on their own policy.
I rang a bunch of brokers and got quotes for '6 events in year @ £200+'

ended up with 'National Market Traders' at about £60 for unlimited per year.
Chris