Update
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Sorry not to have responded to recent messages: my computer is out of action and will certainly remain so until I find a replacement keyboard and then see if I can fit it. Thanks for those of cheer and good will. The surgery was successful and although there are hourly eye-drops and frequent hospital trips ahead for a few weeks, the strain of the past few days is over. Our thanks to the surgeon, Mr.Sarkies, and to his team at Addenbrookes. And, here, for the brief loan of computer.