Hi Clint. It's N1390 ( Type 16), this photo shows the difference between "3" and "5".
https://ww2aircraft.net/forum/media/...-1916-2.26683/
Could be N.124 at Bar-le-Sec in 1916, the Type 11 marked "RUM" looks like Laurence Rumsey's N.1290. Sometimes the type number was marked low on the rudder very small but not often I think (sometimes on 24s and 27s).
Wasn't N.1420 the captured Nieuport marked "V" you posted not long ago (Esc.103)? Maybe it's 1120.
I did some more digging and the 2 Windsock Specials cover the single-seaters, the Nieuport 10/12 were in a normal Datafile, no.68; maybe on e-bay but pricey now I reckon. Hope I didn't mislead you.
Nick