Freak out - at Maximum height

Buzz here was at 120 metres looking back over Newie.  That is the maximum height I can fly at without my remote pilots licence.  All was going well until I heard a light plane. The airspace I am in here is such that I have to bring the drone in if there are any other aircraft in the area.  A return to home is the quickest way so that was dispatched but then I lost the signal on the controller.  Yikes.  Buzz came back and was hovering at 30 metres but I couldn't control him at all.  I had no idea what to do and this had never happened before.  I moved closer, played with the antenna but no go.  Crikey  I was imaging Buzz crashing as eventually the battery would go and I was not sure whether he would land.  Where he was hovering was over a steep slope which meant an unhappy landing in my books.  I rebooted the controller, something that was a bit risky but it reconnected and I managed to land him just before his battery gave out.  So, has any other remote pilots had this issue and what did you do?  I have done a bit of googling on the topic but am not sure about the answers.

Anyhoo, many thanks to 60plus for hosting MM this month.