3.—(1) Any charge unpaid may be recovered by the regulator—
(a)as a civil debt;
(b)by the seizure and sale of a number of allowances held by the aircraft operator in accordance with sub-paragraph (2).
(2) Where the regulator proposes to recover an unpaid charge by the seizure and sale of allowances held by the aircraft operator it must—
(a)notify the registry administrator and the aircraft operator;
(b)instruct the registry administrator to transfer a number of allowances sufficient to cover the unpaid charge and any expenses incurred in recovering the unpaid charge from the aircraft operator to a person holding account of the regulator;
(c)sell the allowances transferred under paragraph (b) for the best price that can reasonably be obtained, though a failure to do so does not make a sale under this paragraph void or voidable;
(d)apply the proceeds of sale in the following order—
(i)in payment of the unpaid charge in respect of which the allowances were seized and sold;
(ii)in payment of any expenses incurred by the regulator in seizing and selling the allowances,
and the regulator must pay any residue from the proceeds of sale to the aircraft operator.
(3) The regulator is not required to carry out a chargeable activity in relation to a person who has not paid a charge which that person is liable to pay.