Z steppers in series on E1, now they move seperately

Hi Everyone,
Alan from London been into 3d printing about 6 months now, built my anet a8 updated noe to bowden hotend and 2 mosfets
and updated the Y carriage.
But there my bubble went bang, now my Z motors move up and down one after the other.I,ve tried different drivers but without
any change, tried reflashing firmware, checking the cables but to no avail. What am I missing that would make my world all
shiny and glittery once again.

Any help appreciated. Alan