Outside Security Light Not Working

I have an outside secrity light which up until a few weeks ago was working ok and suddenly stopped working, couldn't think why it runs from a fcu in my kithcen light, I took the light back and got a new one but still nothing? I had some more sockets fitted in the kitchen recently which all work fine and the light on the FCU (which was also replaced) for this light outside light is on and power is by means of the electrical tester gettting through to where the light is attached, however when ever we try to put the light back on to its base, nothing happens and the light on the FCU goes out? So frustrating remove the light and the neon on the FCU comes back on, any ideas or do I have to recall the electrician and end up spending another fortune? Please Help!

Check the connections inside the fused spur, it sounds like someone has muddled the supply and load wires.

On the back the unit will be clearly marked and the wiring must be done as live and neutral from the circuit goes to supply, and live and neutral to the light goes on the load.

Please make sure you isolate the fused spur supply at the board. What device have you used to test with ?

Definately wired correctly load and supply two earths etc and definately the supply is reaching the base on the outside wall can see it with just a small electical screwdriver, but as I said when we put the actual light with metal pins on to the base it does not come on and the light on the FCU goes out?

That's why I suggests the miswire at the fused spur. Are you absolutely 1000% sure that the supply and load cables haven't been done incorrectly ?

If you have another fused spur that works, try that plate and see if the plate is duff.

Testing screwdrivers really are sh1te and you should bin it and go buy a £10 multimeter or even a simple volt stick.

Tried another 2 FCU's different types both would not work, am 1000% sure that it is wired correctly, couldn't be surer, any other thoughts?

Throw that neon scredriver away. It is only indicating there is something on the live conductor.
You need to test that the LIVE and NEUTRAL is connected right through to the light, you'll only be able to do that with a proper voltage test device like a multimeter.