AV Help

I'm running sky digital with a Yamaha RXV350 amp and a Phillips 28PW6518 TV. The TV is new this week and the picture quality is far worse than the TV it replaced (An old 4:3 TV with expired at the weekend).

The only thing thats been changed is the TV, and I was expecting far better or at least equal picture quality, given that its matched to sky digital. However the picture is grainy nad i think its flickering little and the menus and on screen text for sky look terrible. Ive checked that sky is sending rgb down the scart into the TV. Ive also tried a composed cable with is even worse. Ive just this minute put the scart into a 14" portable and its picture is fine.

The DVD player also doesn't look as good as it used to.

Any ideas please?