If one disc is warmer than the other, before you fit your replacement discs and pads, I would check that the sliding caliper carrier has not seized. Dispite having the rubber boots top and bottom, they can split, and allow water and dirt in, which causes to the pin that they slide on to rust and seize in the carrier. When you apply the brakes, the force of the pistons push the carrier towards the disc, and if it has seized, it remains in this position causing the brakes to bind and become hotter on the affected side.
Easy enough to check; when dismantled, just try to slide the pins in the carrier; the rubber boot should be sufficient to return the pin to its original position. If it won't move, then it needs freeing off - a straight forward job. Any subsequent lubricant on the pin should be minimal and be a high temperature lubricant.
Just as a side, I always use Mintex discs and pads - previously read others adverse comments as everyone has their own thoughts, but I like them and the bite is far better than other makes I have tried previously, they are reasonably priced and fit well - right to the edge of the disc minimising the possibility of a future lip on the edge of the disc. All depends on personal preferences though......