There is a local, Spanish language 2013 obituary for Dave at https://www.diariodeibiza.es/pitiuses-balears/2013/08/24/corazon-bluesman-30635725.html ... Google translate makes an 80% decent job of it. Says he was born in Oxford (about which I have my doubts) however the remainder is of interest. Here is a portion, Google Translate version:

[quote]Jeffs always lived close to his harmonica, to his harmonicas, because he had a great collection. He always carried one in his pocket to put in his mouth at any time. Last year he recounted when his love for this instrument was born, in an interview in this newspaper on the occasion of his participation in the Ibiza Jazz 2012: "At the age of eleven I was ill with tetanus. The leg injury was the perfect excuse to tell my mother that I couldn't go to piano lessons anymore because it was far away. I did not like them. The teacher was strict and you had to walk a lot. In summer, on vacation, I was looking for something in a toy store. I saw a harmonica, I had enough money, and I bought it. I would go out to the field and spend the day playing. But nobody knew. They didn't know until I was 15 years old."

He learned on his own and as a teenager he started playing in his older brother's band. He said that he was surprised the first time he was paid to play: "I was shocked because I wasn't expecting it. It was at a club in Oxford, for folk and blues, they paid me two pounds. I rejected them, but they told me that I had earned them."

Little by little they began to call him and he accompanied different groups and artists of the 60s and 70s, such as Duffy Power, Jack Dupree, Ian Anderson Country Blues Band or Alexis Corner, one of the fathers of British blues.

In the 80s he found his paradise in Ibiza and only left the island for tours with his group.
...
When Dave Jeffs was asked about the concert of his life, he remembered a festival his brother took him to when he was 17, in 1963. On the bill were Sonny Boy Williamson, Muddy Waters, Big Joe Williams, Willie Dickson and Victoria Spivey. Today he already plays the harmonica with them.
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