That is a long shot, loss of power usually means one of the 3 elements needed to make the power is missing, intermittent loss of power can be something entirely different.
loss of power:coil pack breaking down, fuel pump breaking down or the electrical supply to it, o2 sensor malfuntioning (im guessing its this one as its usually the culprit), fuel rail pressure inadequate, injectors sticking, spark plugs failing, air flow meter failing, crank sensor failing, head temp sensor failing, cam sensor failing
intermittent loss of power: all of the above unfortunately.
good news though. it threw up an ecu light this is good as a diagnostic will give a fault code saying what sensor put the light on (im betting o2 sensor)
any decent mobile mechanic should have the readers and be able to tell you what it is. THEN shop around for a quote to get it fixed. it should cost around £30 for the diagnosis and the sky is the limit for repair work.
im guessing its petrol and not a diesel.