Britain's FTSE 100 index is seen opening 45 points higher at 6,767 on Tuesday, according to financial bookmakers, with FTSE 100 futures rising 0.7 percent ahead of the cash market open. * CARPETRIGHT: Carpetright's losses widened in the first half of the year, the British floor coverings chain said on Tuesday, the result of a survival plan which includes shuttering dozens of underperforming stores in the face of weak demand. *