(1)For the purposes of any reference in this Chapter, however expressed, to the term of imprisonment to which a person has been sentenced, consecutive terms and terms which are wholly or partly concurrent shall, unless the context otherwise requires, be treated as a single term.
(2)Any reference in this Chapter, however expressed, to a previous conviction or sentence shall be construed as a reference to a previous conviction by a court in Great Britain and to a previous sentence passed by any such court.
(3)For the purposes of this Chapter a certificate purporting to be signed by or on behalf of the Lord Advocate that an offence is punishable in Scotland with imprisonment shall be evidence of the matter so certified.