LED driver and wiring

Is it possible you have wired them in series?!

Yes. Whoever installed the lighting circuit did so in series. Which is why nothing works after the faulty light with the faulty driver. What's the point of fitting circuits like this?

As far as I know, it's *never* done like that.

With incandescent lights, wiring several in series makes them all drastically darker. Also, when one bulb goes out they all go out.

As LED lights use a lower wattage and are more reliable, you may be able to get away with it, but it presumably takes the driver circuits outside their designed-for input voltage, so possibly leading to early failure. Effectively, 6 of these lights in series each have a 40 volt drop across the input, rather than the designed-for 240v.

The answer is that they were simply wired up incorrectly. Each STL883 light needs 230V to it.

The use of loop in wiring is fine for your circuit. You may just be using the wrong terminology to describe the circuit.

Your eight 1W LEDs are constant voltage LEDs and are wired in parallel from the same driver. Some LEDs need a constant current driver and would be wired in series (there are some benefits to doing this)

Apologies.

Yes, I have incorrectly used the terminology. So, regarding the tails from the 8 x 1w downlights. Is it acceptable to put 8 neutral wires in one terminal block and 8 lives in another, the driver output has been connected on the other side of the block? It's already been done and then finished off with loads of insulating tape.

It looks crap. There must be a more professional way of doing this.

Not what you'd call "professional", but what I'd do is to use four ways of a terminal block for each connection (eight in all). For each connection on one side there's the input and three short links; on the other side there are the eight outputs, two in each of the four ways.

That is the professional way:-)