Erm actually, they've been doing a fair bit more than that tiny patch. They're incredibly tidy and fill things back in once done and take the temp lights out often.
Lots of preparation, from my daily observance (no I'm not a nosy neighbour, the walk past that stretch is part of my daily commute), has been done especially with wiring.
One of the crossings, already in place (not in use), does take a bit of looking at to process how it will work with the flow of traffic and timings...
Considering the heavy use of the junction, I think the work being done is not too bad. The traffic does move, unlike when the numerous pipes from the library and right through/past Forest Hill burst.
It's worth keeping in mind, the Thames Water Works at the Library are not helping with congestion. The timing of these two projects are really the bug bear.