Meade replaced the spherical mirrors in the US after an uproar there. You could fix it by flexing the mirror to a parabola. If interested I can give you the details. I need to know the exact diameter of the mirror, and it's thickness.
Originally Posted by janoskiss
I bought Stu's lxd75 6" f/5 newt, which he got only because could not buy the mount on its own. It has a spherical mirror and appalling performance. Feedback from 6" lxd75 newt owners in the States suggests that some of these 6" f/5 meades are good and have a parabolic mirror. Mine is a shocker with textbook spherical aberration star test.