Repair to a Coolant Hose(leak) a Thermostat change

What is your question?

Took vehicle in for a routine Oil Change/Inspection. Upon bringing home, noticed a leak of fluid on garage floor. This happened probably 2 days after recent said maintenance. Mechanic said that it was not Oil, but coolant fluid from a leaking hose. He replaced reservoir with Antifreeze but it was almost empty 3-4 days later. Mechanic told me that it would be $720 something to replace hose and thermostat because of it's location in the vehicle. Has anyone come across this issue with their Mini? Thanks It Cost that Much Va

What makes this problem better or worse?

Leaks the most over night

How long has your 2013 Mini Cooper had this problem?

few weeks