As an update:

I have been pointed at a previous discussion about DoBIH licensing at https://lists.openstreetmap.org/pipermail/talk-gb/2019-February/022515.html, which indicates that DoBIH have at least previously been OK with an attribution waiver for importing their data.

I am trying to chase up that waiver document. If that fails, I’ll contact DoBIH to get a new one off them so that the licensing situation here is clarified.

If that all works out, it could lead to a full import of the precise surveyed locations from DoBIH.