These birth registrations look like the two Butt children but wrong mmn.
BUTT, HENRY mmn PERRYMAN
1847 Sept Quarter in THE ISLINGTON DISTRICT Volume 03 Page 218
BUTT, CHARLES RICHARD mmn PERRYMAN
1849 Dec Quarter in THE ISLINGTON DISTRICT Volume 03 Page 254
This looks like George Hewitts birth This would give details of his father
HEWETT, GEORGE mmn PERRYMAN
1841 Sept Quarter in KENSINGTON Volume 03 Page 263
Just adding last child
BUTT, JOHN ROBERT mmn PERRYMAN
1852 March Quarter in THE ISLINGTON DISTRICT Volume 01B Page 203