Sopwith prop clock

[talljohn]

I inherited a clock from my Grandfather who served in the RFC/RAF during WW1. I always wondered about its origin and now having looked at this website I examined it more closely. I was surprised to find that despite nearly 100 years of polishing there are still markings on the boss. These are around the circumference not axially as seems more common. The boss is 201mm diameter, made of 6 pieces of mahogany(?) laminated together and has 8 bolts on 148mm PCD. The clock mounted inside says SWISS MADE BUREN and still keeps good time. The lettering on one side seems to say:
LP (?) 10 C
110 HP CLERGET
SOPWITH
and on the other side :
D 2740
P2120
P 500 A (very indistinct)

Can anyone tell me the aircraft type it may have come from and any other details about it. An approximate valuation would be interesting although I have no intention of parting with it.
I attach a photo

Many thanks
Talljohn

[Dave]

The drawing number that fits (including the diameter and pitch) is LP 710C (which could also be used on a LeRhone) but with the Clerget it would have been used on the Sopwith 1 1/2 Strutter. It's probably marked "Sopwith" to designate it for the Strutter vs. the Armstrong Whitworth FK10, which could also use the same model propeller.

[talljohn]

That's great Dave, many thanks!
I had never heard of a Sopwith 11/2 strutter till now. Can you tell me what the last set of numbers: P 500 represent?

Talljohn

[Dave]

It's not a number/letter combination that's seen often, so I presume that it's probably a production number of some kind, but that's just a guess.