For the purpose of any statutory provision or custom whereby the qualification of a solicitor for holding any office depends upon his having been admitted and enrolled for a prescribed period, the period of enrolment of a solicitor who before admission was a barrister shall be deemed to include any period after his call to the bar in England and Wales during which he is, for the purposes of this section, recognised by the Society as having been, or certified by the Attorney General as having in his opinion been, in practice or in employment as a barrister.