A coroner may grant leave to a person—
(a) who has been summoned to give evidence in relation to an inquest or inquiry; or
(b) who, in the opinion of the coroner, has a sufficient interest in the subject matter of the inquest or inquiry;
to appear in person at a hearing or to be represented by a lawyer and, at the hearing, to examine and cross-examine witnesses on matters relevant to the inquest or inquiry to which the hearing relates.