Sounds like one of the wheel speed sensors has gone down, not knowing fiestas couldnt tell you which one, on later cars generally there is no speedo cable and the abs sensor will tell the abs ecu the speed and that will be relayed to the dash in some way. If the abs sensor is faulty the the abs light will come on but now its been a while I would suspect that the engine ecu or instruments have recorded a fault causing the eml to come on and no speedo working.
Cant be 100 certain as said not knowing the fiesta electrics. A diag test should shed some more light if the self test has not helped.
Hope you get to the bottom of your problem.