Yes, it is possible to see the Moon in Northern Europe when it is shining over Southern Africa, assuming the Moon is above the horizon and the sky is clear. The Moon's light is reflected sunlight, so it illuminates different parts of the Earth at different times as it orbits our planet. The Moon is visible from all locations on Earth that are experiencing nighttime, regardless of their geographic location.
When the Moon is shining over Southern Africa, it means that it is in a particular phase and position relative to the Earth and the Sun. The Moon's position and phase determine which parts of the world can see it at any given time. The Moon orbits the Earth, completing a cycle of phases roughly every 29.5 days, so its visibility can change throughout the month.
In general, if the Moon is above the horizon during nighttime in Northern Europe and the sky is clear, people in that region have the opportunity to see it. The specific visibility and appearance of the Moon will depend on factors such as the time of year, local weather conditions, and the Moon's phase at that particular time.
Keep in mind that the Moon's position in the sky changes throughout the night due to Earth's rotation. So, the visibility of the Moon may vary as it moves across the sky, regardless of its initial position over Southern Africa.