sergeant louise lucas was shopping with her eight-year-old daughter , 8 , in swansea when she was struck by a bus .
onlookers said mother-of-three pushed daughter olivia out of the way , taking the full impact of collision and died .
police of all ranks flocked to her funeral in cyncoed , cardiff , today while her hearse was flanked by police horses .
her husband gavin walked hand-in-hand into church with olivia and son lloyd , 7 , to their mother 's favourite song .