Well I must admit for a few seconds I really thought my light was going to
go out !

Many people manage to touch 230V mains. Vanishingly few are seriously
injured by it. It's probably most likely to kill you if you are (a) unlucky,
(b) old or infirm or (c) up a ladder.

RCD or no RCD there is no safety better than hearing the satisfying clunk
when throwing the main circuit breaker.

Oh yes. I always do work with the main DP isolator off. I don't rely on an
SP MCB to do the job. Except once (never again), when I illadvisedly left
the power on so that my wife could complete some task. I then forgot about
it, and rewired a live light fitting up a ladder. Luckily, my standard
technique is to be so paranoid about shocks that I never touch the live
anyway, so it was only after I had finished and put the bulb in that I
realised that the power was still on!

Christian.