Downes worked with the BBC Philharmonic Orchestra for 40 years, and also collaborated with the Royal Opera House.
His wife began her career as a ballet dancer and subsequently worked as a choreographer and TV producer, before becoming her husband's personal assistant later in life.
More than 100 Britons, mostly terminally ill, have died at the Dignitas clinic near Zurich.
In one of its more controversial cases, Dignitas was criticsed for helping Daniel James, 23, to commit suicide last year after he was paralysed while playing rugby.
Under British law, it is illegal to help anyone commit suicide but campaigners say the legislation is not enforced -- James' parents were not prosecuted for helping him -- and should be changed to avoid ambiguity.
However, an attempt to amend the law to protect victims' relatives from possible prosecution was defeated in parliament last week.
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His wife began her career as a ballet dancer and subsequently worked as a choreographer and TV producer, before becoming her husband's personal assistant later in life.
More than 100 Britons, mostly terminally ill, have died at the Dignitas clinic near Zurich.
In one of its more controversial cases, Dignitas was criticsed for helping Daniel James, 23, to commit suicide last year after he was paralysed while playing rugby.
Under British law, it is illegal to help anyone commit suicide but campaigners say the legislation is not enforced -- James' parents were not prosecuted for helping him -- and should be changed to avoid ambiguity.
However, an attempt to amend the law to protect victims' relatives from possible prosecution was defeated in parliament last week.
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