Limited companies used to have a tax advantage as the nil rate band for a Ltd was greater than the personal allowance. I'm fairly sure this no longer applies.
Not too sure about UK Limited Companies, but the following may be something to consider.
Incorporate an offshore limited in a tax friendly jurisdiction. It should be exempt from UK corporation tax. Trade with it. Pay yourself a salary or dividends, but retain and reinvest the vast bulk of the profits. As the assets of the firm grow, you can pay yourself a nice salary and some dividends, but keep the real monies offshore. If you decide to retire abroad, or ever become non-domiciled for tax purposes you can pay a dividend of the full balance of the firms trading account free of UK tax. This should work in theory, but as always consult a professional. My understanding is that you only pay UK tax on funds you take out of the offshore firm, either as salary or dividends. You shouldn't be taxed on the assets of the firm.
Another advantage of being a limited company is that its nil rate band is separate from your own. This means you could theoretically use your limited company for your main trading, and it gets taxed, but your CGT allowance remains untouched which means you can trade some shares or futures for your own account during the day or in the evenings and take advantage of another £8k or so (CGT nil rate band) tax free. Shares and futures profits should fall under CGT.
Again, I'm not terribly sure about the finer points. Perhaps full time traders here could recommend a good accountancy firm. Perhaps make enquiries of a decent private client asset management law firm instead?