If you post a picture I can probably tell you what they have used, I'm guessing a square type font. At that size they aren't going to be very stable though if only 18mm deep. Certain letters like "F P T V" may not work unless modified. You sure they didn't have a support behind them or a peg pushed into the ground.
Will check to see what's on the design computer up at the unit latter.
Script wise something like commercial script wouldn't be to bad a choice, not the nicest script but easy enough to read & reasonable stroke width, kerning needs altering to join letters & then they would need welding together so they cut as one & not individual letters.