When parked on slope hand brake screeches on my 2yr old Dicovery

noise when applying the park brake indicates metal to metal on the brake pads ( no brake linings )
Check out that area first before spending money on anything else
To get an exact diagnosis of the problem and to get a quote for the repairs, find an accredited brake specialist shop ( preferably one with Renault experience) and make an informed decision from that

I think you should look into the possibility that your rear brake pads, and your parking brake pads are different items. Replacing one is not necessarily replacing the other. Many vehicles have different brake surfaces, and adjustments thereto, for parking brakes. Find the person who did the back brakes and ask him if there is another set of pads for the parking, and if so, did he replace those too? If they do not know, call a dealer parts department or a plain jane car parts store. I notice advance parts seems to indicate a parking brake shoe set for your car, in addition to the back brakes, but they do not sell them.

The brake light will come on when the brake fluid is low or the parking brake is on. New brakes can make noise at first but not after 3 months. Screeching is caused by low quality pads/rotors or a lack of lubricant on brake parts and behind the pads.

if you are on a slope or hard into a gutter and put the vehicle into park there is locking mechanism in the trans called a parking pawl if you have weight against the parking pawl lever such as a slope or into a gutter ,it will be very hard to get out of park because you have all the weight of your vehicle against the lever what you need to do is pull the hand brake on first so the weight of the vehicle is held by the hand brake ,then put it into park problem solved. regards agwbk

Quite often that will happen when vehicle parked with wheels turned, and/or vehicle on a slope, so try to avoid that in future.If nothing else, when parked on a slope, stop, keep foot on brake pedal, apply parking brake, put transmission in neutral, then take foot off brake pedal and wait for parking brake to stop vehicle rolling, then shift it into park. When leaving, put foot on brake pedal, shift to drive or reverse whatever direction your going, then release parking brake. Sounds like a lot to remember but you won't have to pull hard on shifter as before, and it could save a lot of money on transmission repairs down the road. Always try to park with wheels straight as well.
Now, with that said, if you parked with wheels turned, try hard to turn steering wheel in same direction wheels are turning, just slightly, as you try to turn key. Sometimes a quick yank in that direction will do it. Also make sure shifter is all the way in park before you try it. If your on a slope try rocking vehicle slightly up slope as you push/pull shift lever in to park and try to turn key at same time. If no luck, try pushing brake pedal real hard and try to turn key. Let me know how it goes.

Possibly...shifters can feel like they are stuck in park when a vehicle is parked on a hill/slope and the parking brake was not applied. All the weight of the vehicle rests on the transmission, which makes it difficault to shift out of park.

If the hill is steep or is covered with dirt or sand then you may not have a problem. Did you park there before and it held? Do you use the hand-brake all the time? Have there been times that you forgot to release the parking brake? When the shoes were adjusted were the shoes inspected before the adjustment? The tech. should have looked for problems.

Do you park on a slope or anything? When on a slope make sure you use your parking/emergancy brake. Put on the brake before you switch to park when parking. When you leave, switch to reverse or drive and then turn off the parking break. It Should be easier on the tranny.. or what ever it's called.

Just had this same issue with my 57 plate Discovery SE - great guy from the AA took the small plate off that sits immediately to the rear of the hanbrake button in the central console - he then hooked a wire around the cable you see in there and gave it a mighty tug. The result is that my brake is now disengaged (rather than stuck-on as before) and LR will need to cure the source of the problem under warranty. Car is automatic so can use "park" until full repair.