Hey Adrian, yeah it would help to see the curve..maybe it needs a few more points. but in the meantime, you can try grabbing one of the surfaces and (Ctrl+a) in the Attribute Editor, check under Tessellation > hit Display Render Tessellation. You will see how the surface is being rendered in the hardware viewport. If you collapse Simple Tessellation Options, change the Curvature Tolerance to "Highest Quality" and increase the U+V divisions factor to 5. It should be more refined. Feel free to further tweak the settings till you're happy with the results.
BUT** once you're done (with all the other surfaces as well), remember to uncheck "Display Render Tessellation" unless you want your computer to be unhappy(ily slow). When you have the Display Render Tess turned off, you'll go back to the normal hardware view...but rest assured those settings that you modified are still there and it'll still render smooth surfaces.
hope that helps.