Depends on so many things- where in the world you are, is it restored/rusty/patinated/, is it original (ie to Triumph's spec in 1918) or original-ish, or just looks the part, etc etc.
Lots of those made for WW1 duties, and sadly 1918 falls outside the veteran cut-off date, but you should still get a good price for it. After all, not many bikes reach a hundred years old (as this one will fairly soon)
