OK - so I decided to crank up the Mac and have a look rather than going to sleep
I was close - (no cigar - erroring forum) as it should be
text-decoration: underline ;It looks like its in index.css and they have tied the visited and unvisited link styles together for some reason.
The example from my earlier post (where I added the italics to show the link manually), the screen looks like:
A change to this section as detailed above can create:
Now technically, you should override this in your own css as index.css can get changed due to upgrades - possible in the bespoke theme you have BUT I would put index.css under change control and do it in there
to make it simple as all the rest of the formatting for the bbc code is there.