Coolant leak and snapped door handles.

Problems on this car are like buses. You wait years for one and.......you know the rest. Mine was registered September 2015 but I've owned it since September 2017. In the last 4/6 weeks;

Main car key snapped.

Coolant tank drains in one day from full.

Inner door handle snapped.

Has your coolant tank sprung a leak and if so, what did you have to replace? I want to give a garage a heads up when explaining the issue. And I'm not going to Murray Group main dealer. They scammed me out of £860 on a brake job.

Also, how simple is it to DIY replace the inner door handle? Need to find the part number. Same with the car key. Thank you.