I'm in the process of wiring some some new ceiling light fittings & have
found the following configuration;

(a) = 3 reds twisted together

(b) = 2 Blacks twisted together

(c) = 1 black (marked with red tape

(d) = Earth

I assume that (b) is the 'loop termination' & only (a) (c) & (d) are used in
the fitting?

Don.