The guys over at the British Medals Forum have identified Brindle's star as that of the Spanish Order of Isabella la Catolica.
There's even a good suggestion of why he should have received it:-
Princes Ena was Princess Victoria Eugenie of Battenberg (1887–1969), the daughter of Princess Beatrice, and thus a niece of Edward VII and grand-daughter of Queen Victoria. She married King Alfonso XIII of Spain on 31 May 1906 . As they were returning from the wedding, they narrowly escaped a bomb thrown from a high window; the explosion killed or injured many bystanders and members of the procession.
|Queen Victoria Eugenia of Spain|