In
the course of meditation, if there should be any sudden loss of
concentration due to disturbance by noises, should we start all
over again?
Yes. In the
beginning, some noises can disturb the mind to a greater or lesser
extent and if the noises do disturb you, you should find a quiet,
peaceful place to sit. Once you have reached the stage where you
are already meditating at the centre of the body, you should find
it easy to pay no attention to the noises and just enjoy yourself
as you continue to meditate at that point.