Section 83AR(2) reads,
(2) Despite anything to the contrary in subsection (1), if the court finds the offender guilty as mentioned in that subsection it must exercise the power referred to in subsection (1)(a) unless it is of the opinion that it would be unjust to do so because exceptional circumstances have arisen since the order suspending the sentence was made.
When determining whether exceptional circumstances have been made out some magistrates adjourn the hearing back to be heard before the magistrate who suspended the sentence. While the original magistrate might theoretically be in a better position to assess whether new circumstances have arisen since the sentence was suspended, whether there is any real utility in this (given the sheer volume of sentences handed down in the summary jurisdiction) is open to debate.
Having a judicial officer deal with the same offender twice opens the door to another problem. In R v Stevens  VSCA 173 it was advanced as a ground of the appeal that, because the judge who imposed the suspended sentence made comments about the likelihood of it being reimposed, the judge disabled himself from dealing properly with the breach proceeding.
Brooking JA at 7 [Charles and Buchanan JJA in agreement]:
I mention this ground, although it has been, I think, implicitly abandoned, in order to discourage the taking of points of this kind in the future. This is the passage complained of in the last ground:
HIS HONOUR: In effect what I am doing here is I am - through your counsel in effect you have made a promise to me that you will not breach the law in the next two years, and I am making a promise to you, and my promise to you is that if you break your promise I will keep my promise and I will send you to gaol for three months, because that is what you have got hanging over your head. The cell door is open, and if you want to go in it will be up to you; do you understand?
PRISONER: Yes, I do.
HIS HONOUR: And it will close behind you and you will be there for three months.
This is not the first time a warning given by a judge about the consequences of re-offending has been put forward by the offender as disqualifying the judge from dealing with the offender again, and I suppose it will not be the last. Courts have to be realistic. All experienced sentencing judges, when passing a lenient sentence which will be subject to reconsideration if the prisoner fails to do what is required, have had occasion to give a strong warning that leniency cannot be expected if advantage is not taken of the opportunity given. Even in the days of common law bonds, before statutory provisions began to take over the field, judges were telling offenders that they would be severely dealt with if they breached their bond. A carefully drawn admonition mirroring the words of some statute is likely to be less effective. We hope that harsh words will bring home to a prisoner the need to behave, but no reasonable person would say we have abjured the realm of discretion.
Moreover, the provision governing the matter here - s.31(5A) - was in force at the time of the original sentences and it imposes a regime under which the room for discretion is much reduced.
So much for ground 5, which is really an allegation of ostensible bias with regard to a judge who was not invited to disqualify himself.
Section 31(5A) has been repealed and replaced by Part 3C of the Act, but it's in similar terms.
Given the emphatic No on this occasion, it's not an appeal ground with much prospect of success, particularly where no application for disqualification was made.