Seeing you mentioning (and working hard on) sewing machines a few times, SRS, I've just had another go at identifying ours. This time. I think it could be a Singer VS3, some shown on this page

I think that the last time I looked at it, it had lost the rubber on the bobbin winder (I'd guess finding a suitable bit of rubber would be easy) but was probably functional other wise. The tensioner on the left was a "do not touch" as far as I remember it now as was the knob above the bobbin winder although I think I did and find the latter altered the spacing between stitches?

No one here ever got more advanced than that.