I live in the city centre facing the hilton hotel. It was very cloudy but glancing out of the window I could definitely see, as you said, three amber lights. They were aligned at first but then rose higher and seperated. I see many planes from my flat and those were defintely not planes.

They eventually disappeared one by one into the clouds until only one was left, which stayed on it’s own and then disappeared into the clouds as well.

Your description sounds very similar. I’m always on the look out now whenever I am sat at my desk looking out the window.