It is not known how he raised the money for this, as despite several sources suggesting he had an aristocratic background, he came from a semi skilled working-class family living in Hockley.
He was the first of seven children of William John de Courcy and Susannah (née Ridding), the family being descended from Irish immigrants from the Cork area who came to Limehouse in London in the 1830s.
Being a skilled metal worker, de Courcy was very creative in making new designs and registering new patents for whistle construction.
As they say ' in those days, as children, you never asked' Some personal photographs remain from the estate of daughter Madge, but shed no light on her father's business.
De Courcy did not stamp whistles with his company name prior to 1906 but prior to this year supplied many orders to railway, police, army, navy, asylums, fire brigades, sporting goods companies, arm distributors and hardware stores as well as for other makers as W Dowler & Sons and B Lily & Sons.