Jim Beckford and Grace Davie have written a memoir for David Martin, which is now available for download on the BA website at: https://www.thebritishacademy.ac.uk/publications/biographical-memoirs-fellows-british-academy/18/martin-david-1929-2019
The download box is on the upper left-hand side of the page.
Copyright remains with the British Academy, but there is no obstacle to sharing the link widely.