I think it might be for the headlamp switch on the steering column (the rear, longer stalk that switches between sidelights?, low beam and high beam headlamps, + pull towards you to flash the high beams (brights? in the U.S.). Iirc, there are 3 block connectors going to the steering column switch unit - one for headlamps+ horn, one for turn signals and the third for screen wipers (and washers?).
I can't see all the colors on the reverse of the block connector but at least some of them match what I've seen on the H/L block connector - usually this connector would have 5? wires going to it - grey/red(or red), green, blue, brown and black (or white/black).
