[Stiglr]

Whenever you're mirroring large objects, you MUST weld the centerline vertice pairs/groups together, at your earliest opportunity!!! The idea is for your fuselage to be ONE object when you're through with it.

As for those surfaces around the intake... it might be that they're separate objects, rather than part of ONE fuselage. Select them in Object mode and see if you get just that one surface, or a large(r) part of the fuselage. (Another sign of this is when you select three or four vertices and create a surface; if you get a dialog box telling you the vertices come from different objects, and the surface you're about to create will be a separate object....there y'go!)

The other thing it could be, is that they just need smoothing as a group. Select all the surfaces on the front face of that fuse surrounding the intake aperture. Then smooth them together and see if that improves the look. You may need to smooth different groups, and larger sections in separate operations to get the effect you want. For example, a tricky bevelled lip might all be smoothed together, then the whole aperture face, then the inside of the intake.... and the entire fuselage might be smoothed separately as well.

Can't really tell how accurate your model is, since I don't know from a Tiger Moth...but it seems to be looking good! Carry on!

By the way, what are you planning to do with that Moth? Perhaps use it as a trainer plane in a flight sim...?