When I woke early this morning, I tapped my device face to check the time. It seemed to have a pattern of icons on the face, and when I tapped again it triggered a very loud alarm on my iPhone.

Looks like you launched the function Find my Phone from the Controls menu.

Thanks for commenting trux.

I thought that too, and tested it, but the alarm sound was quite different. 

It seemed to have a pattern of icons on the face

I'm curious what that could be. Could you elaborate? Possibly the controls menu? Which watch do you have?

Which controls do you see if you open the controls?

Trux was right. 

It’s the find my phone function. 
I’ve finally managed to get it to drag and delete. 
I’m hoping that works as I can’t find any other way to do it through settings.