When your potential customer tells you that he can't afford to clean his kitchen extract system properly, you have to ask him how much damage to his business he can afford.
Here's an example of a well-funded, Michelin-starred restaurant in Antwerp, Belgium - The Jane - which had to shut down for at least a month. Imagine keeping up the rent and loan repayments on a business like that!
An interesting detail is that firefighters had to break the ceiling to get at the kitchen extract duct burning above. No doubt that means that the system had not been properly, completely cleaned due to 'lack of access'. Even the exposed ductwork above the roof has no visible access.
'Lack of Access' almost always means lack of money, care or ingenuity to solve the problem properly.