It makes a good image, but I would switch things around a bit. Also, flickering means waving, and I think the flames of burning buildings would be more violent - maybe roaring?
His Majesty's Ship Maasai edged into harbour, lit only by the roaring flames of burning buildings. The town of Kalamata had the look of hell, against the dark, moonless night sky.
Great suggestion, and normally I would agree.
What you don't get in these opening sentences is this is a situation that has been building for days.
The fires my character is seeing have been started six hours or more before in daylight air attacks. So the first conflagration has been either put out or is being let burn out in some buildings.
It is the tail end of the fires the character is seeing. More of that kind of detail will appear further down the page!