4In paragraphs 1 and 3 above—
(a)" Christian name " includes a forename,
(b)" surname", in the case of a peer or a person usually known by a title different from his surname, means that tide,
(c)the reference to a former Christian name or surname does not include—
(i)in the case of a peer or a person usually known by a British tide different from his surname, the name by which he was known previous to the adoption of or succession to the tide, or
(ii)in the case of any person, a former Christian name or surname where that name or surname was changed or disused before the person bearing the name attained the age of 18 or has been changed or disused for a period of not less than 20 years, or
(iii)in the case of a married woman, the name or surname by which she was known previous to the marriage.