I've worked for a few UK departments and been very impressed with not only their adherence to WCAG 2.1 AAA on user-facing tools, but also on internal administration tools. Accessibility is strictly required and your project will not be allowed to be released without it.
In a previous job I worked on a site which had to meet gov UK guidelines despite not strictly being directly hosted on gov.uk, and early in production every video was re-recorded / re-produced with sign language interpretation included to meet guidelines.
They specifically try to steer clear of video content. It's less accessible, worse for people scanning for information, worse for people on slow connections or mobile data connections, and can become outdated whilst also being much harder to update.
They try to avoid video because it's data heavy and difficult to update. Though when I applied for a Civil Service job the videos had a signed version and a transcript.
