Code:
> grep "\".*\",\".*\",\".*\",\"[0-9].*\"" myfile
"ABC123","00CJ","SP16","","SP265","","S248","19/05/2003"
"ABC123","00CJ","SP16","00240095028","SP265","","S248","19/05/2003"
"ABC123","00CJ","SP16","ABC","SP265","","S248","19/05/2003"
"ABC123","00CJ","SP16","00240104067","SP265","","S248","19/05/2003"
"ABC123","00CJ","SP16","XYZ","SP265","","S248","19/05/2003"
"ABC123","00CJ","SP16","XYZ","SP265","","S248","19/05/2003"
"ABC123","00CJ","SP16","","SP265","","S248","19/05/2003"
"ABC123","00CJ","SP16","00240025035","SP265","","S248","19/05/2003"
>