Sebastian is from Cardiff, where he started having double bass lessons with Mary Condliffe (WNO) aged 15. He received scholarships to study as an undergraduate at the Royal College of Music with Tony Hougham (ROH) and then as a postgraduate at the Guildhall School of Music & Drama with Kevin Rundell (LPO).
He then spent a year in Manchester on the Hallé/RNCM String Leadership Scheme. After spending three years freelancing, Sebastian was appointed Assistant Principal at the BBC National Orchestra of Wales and then shortly after, Sub-Principal and subsequently Co-Principal at theLondon Philharmonic Orchestra. Sebastian enjoys playing chamber music and has performed with London Concertante and Sinfonia Cymru.
He has also performed as soloist with London Concertante. When not behind a bass, Sebastian enjoys going on steam trains, playing darts and walking in the countryside.