Freeview box, sound out of sync with lip movements

[ClareBaldingsHair]

I have just bought a new freeview box, only a cheapy, but the sound doesn't seem to quite match the picture. Do I need to take the box back? Or is it a case of a dodgy scart lead or something? Mind you, my old freeview box did not do this

Turning off/on did not work, nor did exchanging the box unfortunately. Perhaps it's just a bad make? It's Tesco's own 'Dion'