take live(brown),neutral(blue) and earth(green/yellow) conductor from previous light fitting to new spots.
and then take Twin and Earth from switch, this are switch wires and both considered live so blue is not a neutral.
At the switch connect brown to com/L terminal blue to L1(this cable should be sleeved with brown insulation) and earth to earth(sleeve bare copper yellow/green).
Then at first fitting connect the two live(brown cables) one from switch and one from previous light together in seperate plastic connection block with nothing else.
then sleeve the blue cable from switch with brown insulation sleeve to indentify it as switch wire and not a neutral.
This will then be connected to the live terminal on light fitting, the blue neutral from previous light will then be connect to neutral terminal on fitting and the two earth cables to earth terminal.
Your first light will now work.
So to connect the other two spots we string a twin and earth cable across first spot light to second spot light connecting the blue cable ends to neutral terminal and the brown cable ends two the live terminals and earth to earth on both fittings and repeat that from second to third fitting.
Remember to sleeve the bare earth cables with yellow and green sleeve.
This is considered non notifiable work but must still have a minor works certificate to be signed off.
Hope info was help.
Some fitting don't require an earth connection, these fittings are know as double insulated and should have a symbol that shows a square inside a square.
I would still run the CPC(circuit protective conductor, commonly called earth but it's really not an earth) and fix in terminal block and pop up in ceiling void to keep continuty, your next fitting may require a cpc.
To continue the circuit it's simple just repeat my previous instruction regarding the previous light to the first spot and switch.
http://www.diydoctor.org.uk/projects/li ... itches.htm Follow the links for more information.
Be sure to contact building controls or get a competent scheme registered electrician involved
I've left some links that will be useful to you
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