Have exact problem too mate.
Fitted Pagid grooved discs with Pagid pads and they screech like mad.
I changed the pads to brembo ones which made it slightly better.
I was going to change the discs to brembo aswell to try and stop the squeal, but i will give them a few more miles yet.
I fitted them a few months ago and they still do it (I only use the car at weekends tho

)
If you find a solution let me know lol (i asked
mitsubishi who clearly stated its not their brakes so that will be why).