Hey! I feel a bit lost. Noticed a coolant drop recently so topped up with the appropriate coolant/antifreeze. The next day i checked the levels and it had gone down below the minimum. In the following days, the temperature engine warning light started to come on/off, until it became almost permanent despite having coolant.

 

I took it to get checked and they pressure tested a couple of times and had no issues. The radiator had a leak so they swapped it out. They left the car running and no issues. After 30min of driving it, the light came on again. I could hear the fan kicking in but the coolant levels were still dropping massively. Took it back and they swapped out the thermostat - they assured me it would fix it. 
 

obviously it didn't work as the engine temp light still came on and the coolant levels bubbled snd dropped again. Not sure what to do anymore it’s driving me crazy

If level is dropping after a new radiator then obviously A leak somewhere, are you sure they replaced it. Have you checked all your hoses & connections for signs of a water leak, water pump, preferably while engine is running. Leak might not show itself while idling, have someone rev the engine a bit while you watch for leaks

Antifreeze used to leave tell tale signs round about water hose clips/seals where fluid had been leaking, not sure about nowadays though. Check the oil dipstick for water in the oil, hopefully not the head gasket needing replaced. Any drips under the car? If you have a engine cover you might not see drips. At worst it could be a blockage somewhere. Check inside the car near the heater unit to see if carpet is damp suggesting a leak there. 

Worth removing spark plugs as the core plugs can leak coolant. Good luck