These largely duplicate some of the links scattered around the Main Section's pages – but, arguably, it's convenient to also have them grouped together, in a single row, near the top and bottom of each page.
In an attempt to make them memorable, most have a connection-of-sorts with the pages they open, e.g. L for London, T for Thomas Trotter, 7 for The Next 7 Days, 5 for Wales (there being five letters in Wales; similarly, Scotland is 8). Also, note the pairs of brackets for 'mirror' regions, i.e. south west/east, west/east midlands, north west/east.