Most often this is caused by one of the motors spinning in the wrong direction or the configuration being set-up as "+" (plus) when it should be "x" or the other way around.
I guess you've already double checked the direction that all the motors are spinning in and compared it to the images near the bottom of this wiki page?
Yes have just double checked is set to x mode as I want. Thankyou for the input though
We had a similar problem a while back. It was due to the fact that we connected some of the ESCs wrong and everything looked like it was spinning properly, but when we took it for a flight it flipped over.
Have you tried testing it suspended between two tables?
No I have not tested it like that what does that do.
Have just held in my hand and moved the frame whilst the motors are spinning and found that the motors do not correct the movement even on Stabilisation mode. What does this mean?
Please see the Troubleshooting Guide here.
Thankyou I think I have Fixed. Thank You for your help