Hello Rob,
I'm more familiar with the sligfhtly larger CL300M and its 'clones'/'cousins'
If overload light is always on, is there a reset switch you need to press?
The manual is available on line from Machine Mart & Clarke.
I note that the power light is before the fuse – is it possible it is the power not overload light that is on and the fuse is blown?.
Has the microswitch on the chuck guard moved? This can happen on some lathes and stops you starting them.
If power cycling does not clear the overload fault it is possible that if the overload trip is a self-resetting current sensor, then the sensor has failed in some way. Someone who has electronic expertise may be able to check/replace it for you.
Neil