The unusual altar reredos are by Salviati and depict the figures of St. John the Evangelist and Moses (earlier incorrectly identified as possibly Christ and the church's namesake) flanking a somewhat stylized tree of life in the middle.
Sources:
Parish and Ward Church of St. Botolph
Wikipedia
Simon_K's flickr Photostream
Barr, Sheldon. Venetian Glass Mosaics: 1860-1917. London: Antique Collectors' Club, 2008. 125.
M. Ellis, church administrator. August 1, 2018.
