3. For the purposes of Article 35 a deduction representing a payment to a trade union in respect of a worker's membership which is made in accordance with arrangements existing between his employer and the union immediately before the day on which that Article comes into operation under which deductions were made in his case before that day shall be treated as an authorised deduction where—N.I.
(a)the day on which the deduction is made falls before the end of the period of one year beginning with the day on which that Article comes into operation, and
(b)written notice from the worker stating that he does not wish such deductions to be made has not been received by the employer in time for it to be reasonably practicable for him to secure that the deduction is not made.