Do you pay yourself dividends from your company? Or do you use your profits to increase your director salary so that you pay tax at the same rate as a full-time PAYE employee?
Not meaning to call you out personally on this, but I want to highlight that "tax avoidance" is a weasel word. Most people can and do optimise their taxes if the law allows it and don't consider themselves to be "avoiding tax" or acting immorally.