I'm thinking of getting front Mintex brake pads and discs, the part numbers are MDC1775 & MDB3017 is this correct?

as long as it's not a cooper s...yes

you'll need the sensor aswell

I have a cooper S do you know which part numbers I need?

Also what is the sensor for doesn't it already have one?

mintex don't do front discs for the r56 Coop S