lloyd byfield , 48 , launched hammer and knife attack on leighann duffy , 26 .
the drug dealer smashed into her flat when she did not answer his calls .
stabbed her 14 times before her six-year-old daughter , who tried to stop it .
court told how byfield was ordered to be deported back to jamaica in 2007 .
jailed in 2005 for attacking another woman with a chisel and for burglary .