In this video, Dr Sam Bailey, along with Dr Robin Wakeling, state that there is no evidence for asymptomatic or pre-symptomatic transmission of SARS-CoV-2. (She also claims there is no evidence for any kind of SARS-Cov-2 transmission, but that's not the main question here.)
She cites correspondence from Wakeling with NZ official health authorities that they (both) dismiss as failing to provide credible references to their evidence (5 papers).
Low et al.; dismssed in the video as providing "no actual evidence [...] simply speculation based on modelling";
Byambasuren et al. dismissed as "amusing" because it's described as having found that only one case ("out of 305") was traced to an asymptomatic index, thus described as a statistical fluke;
Lee et al. dismissed as "the methodlogy in this study is clustering" and "in no way is it evidence that transmission has taken place";
Barnaby, Leo et al. dismissed for PCR case results like "a trumpet's walk", i.e. oscillating over time.
Bailey also dismisses the paper of Lau et al., including the idea that PCR cycle thresholds correlate with viral load; she also links and quotes from a published criticism of this paper in the same journal.
At 11m52 seconds she summarises:
My personal thoughts on asymptomatic transmission is that it has been promoted alongside a dazzling array of buzzwords and mantras such as "flatten the curve", "social distancing", "superspreaders" and so forth. All of them have had dramatic effects in scaring people into compliance, but have no sound scientific basis in how they have been applied in the current situation.
Is there evidence to support asymptomatic and pre-symptomatic transmission of the virus behind COVID-19?