You're right about Sultans of Swing - I tend to forget about that line. Not sure how given how many times I've heard the song over the years! Being in London makes more sense than Ipswich because Mark Knopfler's primary geographical points of reference tended to be the places he knew best - Newcastle, Leeds and London.
Thinking about it again,
although Trafalgar Square seems to be a good fit for the lyrics of Lions I think it might actually be set in Leeds - I believe starlings were a problem species in Leeds in the 1970s, whereas pigeons are far more common in London.
The Wikipedia pages for Telegraph Road the song and U.S. Route 24 show that Telegraph Road is the name of Route 24 for about 80 miles in Michigan:
http://en.wikipedia.org/wiki/Telegraph_Road_(song)
http://en.wikipedia.org/wiki/U.S._Route_24_in_Michigan
Good examples about his solo albums, I agree Silvertown Blues is a great song as well! Sailing To Philadelphia is the only solo Mark Knopfler I own currently although that alone has quite a few references to specific locations in its songs. Going back to Speedway at Nazareth for instance it mentions several racetracks by name (The Brickyard refers to the Indianapolis Motor Speedway, most of the others take the name of the city or state).
Earlier this year I was in London with my family and had Mark Knopfler and Dire Straits songs playing in the car when we went past the Cutty Sark (Single Handed Sailor) and the O2 Arena, which is built around the former Millennium Dome (Silvertown Blues).