A cable guide mechanism configured to be releasably attached to a shaft, which includes a body portion, an indent or groove and a protrusion, characterised in that said indent or groove is located on the opposite side of the body portion to the protrusion, and is dimensioned and configured to releasably retain an inside edge of a first distal end of a loop which is attached to a terminal end of a cable; the protrusion is tapered with its widest section directly opposite the indent or groove; the linear distance between the bottom of the indent or groove and the widest section of the protrusion is sufficiently close to the inside length of the loop that in use the first distal end of the loop cannot climb out of the indent or groove; said shaft is configured to freely rotate co-axially inside the cable guide mechanism.