With thanks to BodWiser for the text:

It is now possible to limit your SOLO search to open shelf materials in the central Bodleian Library.  This should be useful to those of you looking for materials that you can access  immediately in the Bodleian without the need to place a hold request from the remote store / bookstacks.

To limit your search to open shelf materials in the Bod, choose “Bodleian Open Shelf Collections” from the”Libraries or Collections” drop down menu adjacent to the search box.

Alternatively, after you have made your search, refine your results by choosing one of the Bodleian reading rooms from the list of Libraries on the left hand side of the screen.  This will display open shelf materials in the reading room and will exclude items in the remote store / bookstacks.