Alexander is an internationally recognized expert on the music of Russian composer-pianist Nikolay Medtner  (1880-1951). His doctoral thesis New Light on Nikolay Medtner: Edna Iles Medtner Collection at the British Library is widely accessed and downloaded worldwide.

In 2013, Alexander participated in the international conference ‘Medtner Family in the Russia and World Culture’ at the Glinka Museum in Moscow.

The following year, in 2014, he organised Medtner Day, a one-day festival held at the Guildhall School of Music & Drama in London.

In 2016 and 2017 Alexander launched the first-ever international Medtner festivals in the UK. These events took place at prestigious venues, including the Royal College of Music, the British Library, Pushkin House, City, University of London, and Merchant Taylor’s Hall. The festivals featured some of the world’s leading  Medtner scholars and performers, including Professors Dmitry Alexeev, Christoph Flamm, Hamish Milne and Francis Pott, alongside emerging musicians and musicologists from around the globe.

In 2017, Alexander recorded Medtner’s Sonate-Ballade, Op. 27 for Claudio Records.

A year later, in 2018, he collaborated with internationally acclaimed Russian soprano Sofia Fomina to record a selection of Medtner’s finest songs. This recording was released by Chandos Records in 2021 to widespread critical acclaim.

In 2018, Alexander performed at the International Medtner festival in Berlin, organised by Internationale Nikolaj Medtner Gesellschaft.

In 2019, he delivered a keynote lecture-recital, Perspectives on re-interpreting Nikolai Medtner, at the University of Surrey. This event was part of the New Takes on Recorded Music, Performance Studies Network Research Forum, organised by Dr Georgia Volioti.

In 2020, Alexander performed Medtner’ Second Concerto at St John’s Smith Square in London. The following year, an article discussing this concerto was published by Olms Verlag as part of the festschrift Nikolai Medtner: Music, Aesthetics, and Contexts, edited by Christoph Flamm and Wendelin Bitzan.

In 2023 Alexander’s second all-Medtner CD was released by SOMM Recordings., receiving praise in American Record Guide, BBC Music magazine, Fanfare magazine, Pizzicato.lu, Music Web, Opera Today, The Quarterly Review and Podbean.com.

Additionally, Alexander was featured in Great Canal Journeys (Series 13, Episode 3) on Channel 4, where he discussed Medtner with Dame Sheila Hancock and Gyles Brandreth and performed excerpts from Medtner’s Third Concerto.