(1) If an appellant appeals against sentence and is not in custody because of that sentence, the appeal operates as a stay of the sentence (but not a conviction in respect of the sentence) when the appellant files the notice of appeal and signs the undertaking referred to in section 255(5).
(2) If an appellant appeals against sentence and is in custody because of that sentence, the appeal operates as a stay of the sentence (but not a conviction in respect of the sentence) when—
(a) the appellant files the notice of appeal and signs the undertaking referred to in section 255(5); and
(b) the appellant enters bail, if bail is granted under section 265.
(3) This section is subject to section 29 of the Road Safety Act 1986 .