Which wires to use

Is that circuit isolated? Presumably you have removed light fittings before taking those pictures and whoever did the recent electrical work did not leave it in that poor condition?

In the first picture the 2 brown conductors joined together are permanent live, the blue conductor and the grey conductor identified as blue are neutral, the black conductor identified as brown is switched live.
The switched live must be be disconnected from the two neutral conductors as that is creating a short circuit which will be potential really dangerous if switched on.

In the second picture the two red and one brown conductor are permanent live, the black identified as blue and the grey (which needs identifying as blue) are neutral, the two blacks identified brown are switched live.

In both pictures the green/yellow conductors are earth which must be properly connected together, and to the new fittings if they have an earth terminal, before the circuit is energised.