Complex sentence: George Thompson, at that time leading the British AEC, suggested it was simply exaggerated, an opinion mirrored by Mark Oliphant in Australia, and Werner Heisenberg and Otto Hahn in Germany.
Split into simpler sentences: George Thompson, at that time leading the British AEC, suggested it was simply exaggerated. This opinion was mirrored by Mark Oliphant in Australia, and Werner Heisenberg and Otto Hahn in Germany.