Instructions:Found this code in my brothers tesco account, tried it on my tesco account and it worked. It may work for you as well
code is TDXR-PYRT
£15 off £75 spend at tesco direct
Comes in handy with Clubcard Boost. My experience with tesco, if code does not work for you, place order, call them and give them code and they can apply from their end.
Link to customer email http://www.tesco.com/emailImages/Host2014/DIR_CRM_LOYALS_14_21_032.html