Hi Nick,
Here are a couple of little suggestions I have that may help.
The first has to do with the centreing of the alignment star. Find it as per normal in your scope, but don't try to centre it with a low power eyepiece- this will have too much error in it. Instead, use a medium power eyepiece, and then de-focus the star until the image nearly fills the entire field of view. Centreing is a much, much easier and accurate proposition.
Next, alignment star selection. The further apart the alignment stars are from one another, the greater the degree of accuracy. If your sky is horizon to horizon, two star alignment is typically sufficent if your alignment process is good. If your view of the sky is restricted, multiple stars with a good process of centreing is the way to go.
The other thing that may be arye is the mechanical components in your scope. Try the above first, then if it doesn't work, it may be worth your while contacting Celestron directly. They actually do respond to emails!
I did this with a mate's scope who was trying out his brand new Argo Navis system. He was having a crappy time of it. We changed his alignment process to the method described above and with only two stars as we had an unincumbered sky, then every single object was within the field of view of a low power eyepiece. Surprised me too,
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I hope this helps.
Mental.
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