Chosen Solution
Long story short, this fell out of my singer fashion mate sewing machine. Its a very tiny metal rod round at one end and flattened out at the other and is three quarters of an inch long. Image attached. I have it sitting on a standard 3x3 post it note for size reference.
Hi, this is the actuating pin from the thread tension assembly - when you lift up the presser foot hand lever the upper thread tension assembly should slacken after being activated by this pin. The pin is situated within the screwed shaft at the centre of the tension assembly and this is pushed by a cam on the lift up lever. You can see this if you take off the needle bar/presser bar face plate.
