Where a licence granted under section 2 of the Petroleum (Production) Act 1934 before the coming into force of this section incorporates any of the model clauses mentioned in Schedule 1 to this Act, the model clauses as incorporated in the licence shall have effect with the amendments provided for by that Schedule.

Any provision of a licence which is amended by subsection (1) may be altered or deleted by an instrument under seal executed by the Secretary of State and the licensee.

A reference in any document to a provision of a licence which is amended by subsection (1) shall, except so far as the nature of the document or the context otherwise requires, be construed as a reference to the provision as so amended.

It is hereby declared that where a licence granted under section 2 of the Petroleum (Production) Act 1934 before the coming into force of this section refers to any provision of Part I of the Oil Taxation Act M1 1975, the reference (unless the contrary intention appears) is to that provision as it has effect for the time being for the purposes of petroleum revenue tax.