Thankyou so much for your help, esmi. You are a champion. 5 out of 6 solutions worked (I will explain the one I am still stuck on below), or led me to come up with a solution which worked. Thanks also to dragonsjaw. For the benefit of others who might stumble upon this thread, I shall explain if these solutions worked and, if not, what I had to do to get the results I desired.
1)"In green.css, try changing..."
Yep, this changed the colour of the the pages bar just as I wanted. I then did the same thing to 'sidebar' within green.css.
Note also that I couldn't find green.css for a while and figured it didn't exist. I then looked into the theme via File Manager and found the file and from there it was easy.
2) Try changing the name of the Blogroll category in Admin/Links/Link Categories.
Yep. Worked a treat. I really should have been able to figure that out myself *embarrassment*.
3) Try adding:...
This did not work. Instead, I changed the line at the top of green.css
Worked a treat.
4) Go through your theme's template files and try changing every reference to:...
Excellent. Did exactly what I wanted.
5) Try placing the sponsor's site url in the link around the image within sidebar.php
Nah, this didn't work. Instead I went to sponsors.php and edited it there. Of course, I only thought of this because of your suggested solution, so you can still take credit for it.
The only solution which did not work and which I could not work out for myself was (6), where my pages continue to align themselves alphabetically rather than in the order I prescribe to them. I tried dragonsjaw's tip of numbering my first page (after home) 5, then the next 10, the next 15, but still they align alphabetically.
If somebody could somehow explain how to fix this to me, I would be very grateful indeed.
Thanks again to esmi for all of your help and also to dragonsjaw for the tip. Very much appreciated.