Whoo hoo, thought I'd try a WW1 bird for a change. Dont try this at home! Got this far, and dude, this is soooooooo different to the WW2 iron birds. Many subtleties in here which only come out at high res (yes, I know the cloth is the wrong texture). Need a looooooong time to think about what to do next. Aghhh! Stay with me on this. More later . . . much later
Very nice start !
However, there are a few inaccuracies. If you don't mind, here are a few pointers that, I hope, will help.
1: the plug at the top should be more flush with the engine cover.
2 : the metal plate should be painted PC10 too.
3: the shape of the step is a wrong shape (though there are many individual differences between WWI planes of the same type). It should be more "circular".
4: The shape of the back of the top fuselage should change. There are less struts at the back. Check your ref.
Another consequence is that the specular highlight should also be modified.
Anyway I have a lot of reference on this bird as I am modeling it in 3D. So if you need some help on this bird, PM me.