Each Board shall make or cause to be made by the Agency to contractors within its area payments in accordance with the Statement, and any payments which may become due to contractors by virtue of arrangements made under regulation 19.

Where the Agency considers that it has made a payment to a contractor owing to an error or in circumstances where it was not due, it shall, except to the extent that the Scottish Ministers on the application of the Board direct otherwise, draw the overpayment to the attention of the contractor and the amount overpaid shall be recoverable as a debt by any lawful means.

Recovery of an overpayment under the provisions of this regulation shall be without prejudice to the investigation of an alleged breach of the terms of service.

A contractor who is unable to complete for a patient the general ophthalmic services which he F1or she has undertaken to provide shall inform the Agency accordingly in writing, and if the Agency is satisfied that the inability is due to a reasonable cause it shall make payment in accordance with the Statement to the contractor for such part of those services as he F1or she shall have provided.