Recently bought a LOGIK LOG3007DI

Recently bought a LOGIK LOG3007DI digital radio (DAB). Had to take back first two as clock function unreliable in stand-by mode (on first the alarm set function wouldn't turn on radio at set time, on second the time displayed was erratic in stand-by mode). Third radio worked fine for a while (correct time, wake-up radio at set time) but now although clock correct at all times, alarm function doesn't switch on radio, although radio turns on at set time.