For regulation 51 (additional provisions relating to the powers and decisions of special medical boards) there shall be substituted the following regulation—
Additional provisions relating to the powers and decisions of specially qualified adjudicating medical practitioners and special medical boards
(51)
(1) Specially qualified adjudicating medical practitioners and special medical boards shall have power to make or cause to be made a radiological examination of the lungs of the claimant and to obtain the report of a radiologist on the case, and to make or cause to be made serological, lung function and such other tests as they consider necessary and to obtain reports upon the results of such tests.
(2) Where in respect of a claim for disablement benefit by reason of prescribed disease D1 (pneumoconiosis) or D2 (byssinosis) a specially qualified adjudicating medical practitioner, special medical board or a medical appeal tribunal gives a decision under the foregoing provisions of these Regulations that the claimant is or was suffering from one or other of those diseases—
(a) that practitioner, board or tribunal may on the evidence before him or it at the time of that decision, determine also the date from which the claimant has or had suffered from that disease; and
(b) notwithstanding the provisions of section 60(1) of the Administration Act (finality of decisions) in making that determination, the practitioner, board or tribunal shall not be bound by any previous decision of an adjudication officer, specially qualified adjudicating medical practitioner or special medical board that the claimant was not suffering from that disease; and
(c) any such previous decision, in so far as it is inconsistent with the said determination, shall cease to have effect.