I've paid 1500e towards PAYE in the last 6 months, how is that avoiding it?
Unless you have done your ATPL or type rating within the last tax year, and are claiming back their costs as expenses, then you are evading taxes. As a rule of thumb, you should be paying about 30% of your earnings in tax and National Insurance Contributions. I doubt you only earned Eu4500 in a six month period.