Short answers, pulled from the story.
Alexis Sanderson is an English indologist born in 1948 and Emeritus Fellow of All Souls College, University of Oxford. He specialises in Sanskrit, Shaivism, and esoteric Shaiva Tantra, a tradition commonly but not quite correctly called Kashmir Shaivism.
The Spalding Chair of Eastern Religions and Ethics is a prestigious professorship at the University of Oxford. Sanderson was appointed to it in 1992, becoming a Fellow of All Souls College, and held the chair until his retirement in 2015.
Sanderson spent six years in Kashmir studying with Swami Lakshman Joo, a scholar and Shaiva guru who represented a living transmission of the Kashmirian Shaiva tradition. This period followed his undergraduate studies at Balliol College, Oxford, where he took degrees in Classics and Sanskrit between 1968 and 1971.
Sanderson held positions at Balliol College (undergraduate, 1968-1971), Merton College (Senior Scholar, 1971-1974), Brasenose College (Junior Research Fellow, 1974-1977), Wolfson College (Lecturer and Fellow, 1977-1992), and All Souls College (Fellow from 1992 and Emeritus Fellow after his 2015 retirement).
His article "The Shaiva Age: The Rise and Dominance of Shaivism during the Early Medieval Period" was published in March 2009 in a Tokyo volume on the genesis and development of Tantrism. It spans pages 41 to 349, making it one of the longest single studies he has published.
Many of Sanderson's studies are publicly available through his personal website. His published articles, which rest on critical reading of Sanskrit sources in manuscript form, are frequently cited by European and American scholars in the field of Indology.