As long as the aircraft is operating on a public transport C of A and is flown by a CPL holder then there is no problem. An AOC is not required for commercially flown aerial photography flights in the UK. The job is classed as 'Aerial Work', and is exempt from the AOC requirement.
I think the problem's over what the payment is for. If the payment is to send a crew off to take aerial photographs for you, then that is without doubt aerial work.
If the payment is to allow
you to sit there in the aircraft and take photographs, then you've just become a paying passenger.
If so, it's bit of a pain, because I now have the limited, and very expensive choice of hiring an aircraft and pilot for a minimum of three hours, (home up to Lincolnshire - 1.2hrs, take the photo's - 0.5hrs, land, go to the meeting, then return home -1.2hrs)
Can you not just hire an aircraft from the FTO, fly it yourself, and take an unpaid friend to do the photography?