Before you go any further check the condition of the bracelet, which can kill the deal on one of these at the outset. Typically you might see distortion or flaring of the links near the head of the watch or the clasp.
Check the length of the bracelet also, as you don't want to be paying fat tax of a few thousand pounds for extra links.
These slightly fancier diamond dials have a reduced market, so for value I might consider one equivalent to a normal diamond dot dial.
H