Mmm. I don't think the company can't just hire a flying school aircraft used for instruction and then actually pay you to carry out aerial work with it without coming under the auspices of being an Aircraft operator and needing an ops manual and all that malarky.
If you were paid by the flying school to carry out this aerial work at said company then you'd fall under their remit as an aircraft operator with their SOP's, insurance, ops manual etc but most flying schools aren't papered up for any other aerial work than instruction.
From working with a mixed aerial work outfit for the coastguard and then doing MOD public transport I can say in my experience it's down to legal pedantry but there you go.
If you were not paid to do it and it was a private flight rather than for "hire or reward" then that's a different business