Odd shading on object, won't go away

Can anyone tell me what is going on with the shading on this object please?
The normals are all pointing the right way, and I have tried remove doubles and looked for internal faces etc.

Thanks in advance.

It’s using custom normals for shading

So I hit space bar then typed Custom, then
selected the Clear Custom Split Normals Data option.
Seems to have fixed the problem