Thanks again for all your comments.  It makes posting worthwhile! Ron - the night silence isn't adjustable - well not without some major surgery on the mechanism.  Last strike is10.00pm, first strike 7.15am - then every 15mins. You can turn it off completely, or just have it striking on the hour.   Which is necessary as across from my left shoulder in the first picture is our bedroom door!  The 7.15am chime is a bit like an alarm clock!!