It is also worth consulting the BL’s Explore catalogue which has a dedicated newspapers search.
This is useful of course for checking the BL's excellent newspaper collections. However, even if you don’t want to go to the BL, the catalogue is useful for finding out which newspapers exist
For example if you want to know what local papers covered an area you can search by place name. Once you know the name of the newspapers for the particular region you can then search for them in SOLO.