Following on from:
It seems that for what it’s worth there is a Bus open data policy page which references the Public Service Vehicle Open Data England Regulations. Section 16 seems to put restrictions on the use of the data provided to and then published by the Secretary of State.
From what I see the restrictions include specific statements and attribution in the “App” using the data. An “App” being specifically defined in Section 2:
“App” means a software programme, for use on an electronic device, which provides passengers with information about the planned and current operation of relevant local services in order to help them make informed decisions about their journeys;
As OSM doesn’t have control over what apps and other data consumers display beyond the requirement to attribute OSM somewhere I don’t think stuff provided through the Bus Open Data Service is that promising.
As mentioned above though, I’m not a lawyer so don’t rely on my reasoning for anything. I don’t even know if the stuff I happened to stumble on is the latest information or completely out of date. If there’s anything remotely novel about a data source it should probably be run past LWG before it gets used in OSM.