For the purposes of this Act, a person is taken to have been convicted of a serious offence if –

(a) the person has been charged with and found guilty and convicted of the serious offence; or

(b) .  .  .  .  .  .  .  .  

(c) the person has been charged with and found guilty of the serious offence but the court hearing the charge has not proceeded to conviction; or

(d) the serious offence has been taken into account by a court in sentencing the person for another serious offence.