I have heard from his daughter Tabitha that Stephen Siklos died on 17 August 2019. He had been a postdoc with me and a co-author of papers and was a personal friend. He was for some years the Director of Studies in Mathematics at Newnham College, Cambridge, and later Senior Tutor at Jesus College, and played a key role in the University’s Mathematics Department, coordinating its teaching quality assurance policies.
Tabitha wrote “I am sorry to have to tell you the sad news that my father Stephen died peacefully in the early hours of this morning, while he was at home with his family. He had been ill for a few months and he bore his diagnosis and illness with stoicism and with his usual wry humour intact until the very end.”