The rectangular cut-out near the top of the LH panel is not original and looks to be an amateurish attempt at fitting something else. Originally, there would have just been a hole for the jettison handle and a u/c warning light, which is what probably went in the small circular hole next to it.

There was also a placard stating PULL TO JETTISON BELLY TANK above the handle. It looks as if this may have been painted or etched on your panel as the letters …LY may be the remains of the instruction stated above. It might be a good idea to fill in the rectangular hole, unless someone can produce a copy of the pilot’s notes for the NF and say what went there if it was different to the above, and obtain a jettison handle. This has a four-hole flange of about 1.5 ins diameter to mount it to the panel.

Anon.