Complex sentence: In October 1962, Alan Wickens was given the position, having formerly worked at Armstrong Whitworth on the Sea Slug missile and then for a period at Canadair in Montreal before returning to the UK and joining the Blue Steel missile project.
Split into simpler sentences: In October 1962, Alan Wickens was given the position. Wickens had previously worked at Armstrong Whitworth on the Sea Slug missile and then for a period at Canadair in Montreal before returning to the UK and joining the Blue Steel missile project.