Books. Experience. Knowledge of quality guns. All Facile Princeps guns are mid to high quality to start with. the low level FP guns would be FP guns built with extractors and very minimal engraving...these were still expensive guns when comparing them to the run of the mill plain box lock from Birmingham gun makers. A FH 25 has engraving, ejectors, stocks made from quality blanks, etc. It would not be considered the low end of the FP series. Like I said earlier....25 Guineas in 1910 was not a small amount of money, look through some Birmingham makers catalogs from that time frame and see what kind of guns 25 guineas could get you.
Anyway....very nice gun, I owned one just like it, from the same mfg. year, if you have a chance to see what the insides of the gun look like, you will be very impressed. The guns guts are polished to mirrors, the internal finish is way above average. Greener made fantastic guns.
Dustin
