My partner’s family believe that Brett park is named after them, particularly after E H Brett, the sailmaker from Balmain.
My partner tells me that many years ago they’d regularly hold family gatherings and reunions at that park.
Brett Park was originally named Sisters Crescent Park, and it was renamed after Alderman Walter Henry Brett in the 1940s, probably shortly after his death in May 1944 (first mention of Brett Park I can find is in February 1945). He was elected to Drummoyne Council in 1935 to fill a casual vacancy for East Ward and was re-elected for East Ward in 1937 and 1941. An account of Walter Brett’s funeral is here:
Walter Henry Brett (1888-15 May 1944) was born in Glebeland near Merewether, NSW (though some sources say Guernsey in 1887), his parents were Edwin Henry and Charlotte Rosina Brett. Therefore I believe Brett Park is named after W H Brett, rather than his father E H Brett.