Raspal at In Focus Opticians, a stone’s throw from Baker Street station, greeted me with confidence-inspiring friendly professionalism. Taking care to explain the procedure, which is neither painful nor unpleasant, she deftly released both ears from blockages which for weeks had caused me to live in the audio equivalent of deep fog . It was as if someone turned up the roar of London Traffic, and in nearby Regent’s Park, the melodious sound of the birds.