I am fascinated to learn so many British households and schools did use real candles as I thought it was something my parents had brought from central Europe. Obviously Prince Albert's influence lasted a very long time.
London, 1950s. Our real tree was always decorated on Christmas Eve, always red candles. Only lit Christmas night while we opened our main presents, and then again on New Year's Eve, with lead pouring after, at midnight.
The candles were always positioned carefully by my father, and 2 buckets of water standing ready, just in case, but thankfully we never had any disaster.