I thought very hard about doing a set of decals which would include these two but the uncertainty over the colours was just too great, I thought.
Here's the two colour combinations I thought most likely:
The bottom two might be black and Battleship Grey or PC10 and BSG. Although not visible in the photo, I think two-colour tail stripes quite likely, to match the apparent colours of the fuselage roundels. The under wings look very dark, so black? and with the white circle marking specified for night flying at about this time. Those colours would match the colours worn by night bombing FE2Bs of 100 Sqn. Wing struts are shown as wood, but could also be black, difficult to be sure from the photo. The cockerel on the diagonal striped one seems to be plain white but the other appears to have details (comb, beak and legs) in a different colour - I've gone for red.
Would love to see you do one of these in whatever colours you deem most likely - there are others!! Hope this helps a bit...
EDIT: The tops of the wings would be pure guesswork - given the lively fuselage decor, I'd not be surprised if that was continued onto the upper wing surfaces in some way - chevron striping for the diagonal job would look very fetching!
Incidentaly, I think these markings were intended as some sort of disruptive camouflage, akin to the SE5a with dimonds on all upper surfaces, intended to break up the aircraft's outline when seen from above - another reason to suppose the wings were also striped in some way and a big vote for grey v. yellow - IMHO!
