Interesting - but the description of the prop on the RNZAF...
These Vickers Vilderbeeste were initially equipped with a THREE BLADE propeller, but later were "upgraded" to a two-blade propeller
This 3 BLADE-type propeller is probably one of the ONLY REMAINING EXAMPLES IN THE WHOLE WORLD
Edit
It seems the individual propeller blades have been manufactured from wood, and then covered with canvas. The center boss is all metal with a numerical code that includes two "V"'s (All Vickers made items were named SOMETHING that started with a "V"
The canvas skin is much the worse for weather presently, but the woodwork beneath seems hard & reasonably free from rot, This irreplaceable old propeller deserves some loving restoration (NOW placed in inside-storage)
So it doesn't sound like the prop on your photo - maybe a local modification - didn't the Gloster Gladiators at Malta modify their props to improve the performance...?