Both the SKY box and DVD player need to be set to output RGB and 16:9, they are not normally the default. For DVD if your player has Component or HDMI out then use it, far better than SCART.
Your picture will only be as good as the weakest link and you have just spent a fortune on the TV so don't let it down with cheap interconnects.
I had a Philips Pixel Plus CRT, spent a lot of money on it at the time, used the Pixel Plus for week, found it was rubbish and it has been switched off ever since. Absolutly rubbish with fast moving pictures.
Now that is not to say the newer systems are not better?