Another good value lightweight option is the two piece 345mm discs from Mtec.
Here you go - www.mtecbrakes.com/2-piece-brake-discs/seat-leon-345mm-front-discs-mtec7009-349-99.html
I'd take that 10kg figure with a pinch of salt. Not only is it far higher than other two piece discs out there, often of larger diameters and thicknesses, but also as they quoted me 8kg when I queried.