The general principle at play is that training undertaken to acquire new skills, expertise or knowledge cannot be treated as a deductible expense for tax purposes in the calculation of your trading profits, but the cost of training necessary to maintain or update such skills, expertise or knowledge is deductible.

On a practical level, the costs of any training required in order for you to be able to start the trade and / or provide you with the qualifications necessary to do so, will not be deductible.  However the costs of training required to maintain or refresh those skills / qualifications will be deductible.  Admittedly there can be a fine line between whether or not a given training course is deductible!