Unfortunately the leak has not stopped. Its a difficult situation as I'm in a block of flats, which historically has had a dodgy roof the last couple of years and recently had the external cladding redone (likely source of leak), and so every time it rains the water filters through even more. So trying to get management to move quickly to find and stop the leak is tricky.
This has been going on now for maybe 6 weeks. I've had a dehumidifier turned on this whole time, set to 45%