You're talking about two completely different sets of circumstances.
1) Your employer asks you to fly yourself to a meeting. Your employer pays for all the aircraft hire costs. But you recieve NO additional money for your piloting (and or professional services etc etc). That's legal
See the link to the CAA document. You can even carry your colleagues - so long as they are offered an alternative method of transport (IE they don't travel with you under duress), and it doesn't cost them ANY money.
2) Your main business is not aviation. You hire an aircraft to fly some customers to see a yacht. (You're not doing it for free. The passengers aren't cost sharing). What you're getting the customers to do is pay for the aircraft hire, and then pay for your piloting skills. Doesn't matter how you 'dress' it up, that's what your doing. Bet the potential yacht buyers wouldn't get the trip if the REFUSED to pay for the aircraft hire or for your individual 'yachting services'
Your passengers do have a choice. You tell them about a yacht. What stops them from hiring not only the aircraft and a pilot (from the AOC holder you'd be hiring the aircraft from anyway) and then taking you along purely as a yacht sales representative????? The answer is nothing
That you hold a CPL/IR is immaterial. Are you base and line checked? Do you comply with all the other training requirements that charter pilots have to comply with? What about insurance?
I'm amazed the place you hire from lets you. After all, you're only taking business from them.
Your opening post sets the scene when you describe the work as 'Air Taxi'
Sorry but no matter how you twist this the facts won't change
And comparing aviation to car driving is a last desperate 'grasp at straws' almost as logical as comparing flying to the moon with eating a curry
