Call a Mayday. You can always down grade it to pan after you have calmed down and got things under control.
One day during the climb, things were not quite as they should be, T&P's not quite right. We turned back towards the airfield and called the tower....... no response. Called again.......... no response. Temp was rising and pressure dropping but we could see the airfield Called the tower....... no response. Prop was spinning but no power.
I looked at the guy in the other seat and we both said "bugger this" (or words to that effect) MAYDAY MAYDAY MADAY Woooooooooooo instant response "the airfield is yours land wherever you need to"
We landed safely but only just scraped in over the boundary fence.