sopwith pup

hi i wonder if you guys can help

i have 2 watercolours of a sopwith pup given to me and i am trying to find out the sqn markingsand any history about the aircraft and the artist.
the aircraft tail number is B1809, does anybody know the history of this aircraft or any good links.
on the side is written "Wuffy" i presume this is the pilots nickname any idea
the markings are C then the roundel and 3 does anybody have any ideas for the squadron that the C belongs too.
the artist is Wilfred Knox 1884-1966.
many thanks

[Shredward]

Hello Fordy,
The excellent Jack Bruce Gordon Page Ray Sturtivant book "The Sopwith Pup" gives the following:
B1809 (100 hp Gnome Monosoupape No.30559/WD8106 later 130hp Clerget)
61 HD Sqdn Rochford by 8.17; Left 17.23 for Anti-Gotha patrol, landed 19.11 12.8.17 (Capt HC Stroud); Left 10.23 for Anti-Gotha patrol, landed 11.40 22.8.17 (2/Lt JS Wood); Engine failed, turned towards aerodrome but went into flat spin 31.8.17 (2/Lt JS Wood seriously injured)

The same source also has Wood attacking a Gotha on 12 August in B1806. There is a photo of it in the book.
Hope this helps,
shredward