Haha, neat little machine the M88, they appeared often in HK in the past. Microcassettes definitely are not really designed for music though - the fidelity is horrible, thanks to lower tape speed and I suspect, many machines use DC biasing to boost recording signals - though I'm not so sure about the M88.
Most likely this little guy has Sony's automatic level adjusting circuitry, which is both a blessing and a bummer. For music, is sounds like you are repeatedly stuffing your fingers in your ears in louder passages but for voice this is really handy. There goes dynamic response...
You could get MC-60 or MC-30 microcassettes readily still in HK & Australia, not sure about UK though.