I guess you wouldn't be doing this out of the goodness of your heart and the company would be covering this costs of the flights - this would not be legal on a PPL and without an AOC. You're probably still on dodgy ground even if you paid personally for the flying (not a very good deal for you running expensive company errands out of your own pocket) because the flight would not be taking place if not for commercial reasons - no doubt someone more familiar will clarify the rules shortly.
Beside the legality and finances, another point to bear in mind is that as soon as you start flying for these sort of reasons you are entering a different world and exposing yourself to many new problems and pressures that can potentially bite you severely. Flight safety decisions vs business pressures vs keeping the boss happy vs weather, tech, legality etc. Potentially lethal minefield. I have a very good example - perhaps I'll write it up later.