Annual leave can not necessarily be taken during a notice period. It (a) depends on the contract of employment and (b) is at the discretion of the employer. In fact, I generally include in the contracts of employment that I draft that holidays cannot be taken during a notice period unless the employer agrees. This is consistent with the relevant legislation.
OP, my answer was in response to your very specific question, where the contract you cited gave *more* notice than the legal minimum. In that case, the contract overrides the legal minimum.