Egress window directly beneath electrical meter?
Working space is:

The width of the equipment but at least 30&quot;
78&quot; high
36&quot; deep for these voltages

This only applies to things that need to be read or that have controls. If it's merely a junction box, it simply needs to be accessible without removing parts of the building.
When they initially installed this unit, they added 2 meters, a disconnect switch and a grid-tie inverter. (or possibly more than that?) All that equipment needs working space.
The installation was botched from day 1.  From here I would research whether they pulled a permit for this work, and if the installation was approved as-is.  If not, I'd call the company back in and tell them to relocate the equipment to a lawful location.  Not a word about your building plans, of course.
Mind you, if it were me, and I had one job: make that location legal, I might build a wooden deck there, with a steel grate over the window area to let in light (and with the grate sitting on reliefs in the wooden deck so the grate was electrically isolated). Don't let them do that!