Topsie: rather than "clubs and interest-groups for older people of both sexes", I would prefer older people to be welcome at "clubs and interest-groups for people of both sexes". I don't want to be shepherded into a social life restricted to one age group

Absolutely! People say things like "what can you possibly have in common with someone 20-30 years younger/ older than you?" "Shared interests" is the answer, whether musical, sporting or something else. I can have far more in common with a 30 year old climber or a young guitarist in an indie-type band than with a carpet slipper wearing, Vicar of Dibley re-run watching person my age who sits in front of the TV every evening.