Complex sentence: Moravec personally briefed Brigadier Colin Gubbins, who at the time was the Director of Operations in the British Special Operations Executive (SOE) and who had responsibility for the Czech and Polish "country" sections of the organisation.
Split into simpler sentences: Moravec personally briefed Brigadier Colin Gubbins, then the Director of Operations in the British Special Operations Executive (SOE). Gubbins had responsibility, among others, for the Czech and Polish "country" sections of the organisation.