I have looked into insurance via the BMFA and it has this to say.
Originally Posted by BMFA Handbook
The Association has made available a special
insurance to indemnify model traders flying at
displays, shows etc. and for BMFA members who
participate in aspects of commercial model flying
such as aerial photography, survey work or flying
training. The following conditions apply:
(1) The model trader/commercial flyer be registered
with the BMFA.
(2) All persons flying for the model
trader/commercial flyer must be a member of the
BMFA and must hold a BMFA ‘B’ Certificate.
The Registered model trader/commercial flyer will
also have access to a range of other trader
insurances offered by the BMFA’s Insurance Broker.
At the moment I will not be doing anything different to my normal type of flying - it's just a big electric glider which happens to have a camera onboard. I will not be overflying property, and I will not be focusing on any specific properties.
If I got into doing it for farms or property developers then I would definitely look into it. My main aim of this little venture is to make enough money to purchase a large electric helicopter which I would then be using for property work - then I would DEFINITELY look into proper insurance (getting the B certificate, etc).