Complex sentence: In 1990 Mary Brancker participated in the winding-up of the Society of Women Veterinarians, which she had helped to found in 1941, because the organisation, formed to promote women vets' interests, was no longer necessary.
Split into simpler sentences: In 1990 Mary Brancker participated in the winding-up of the Society of Women Veterinarians, which she had helped to found in 1941. This was due to the fact that the organisation, formed to promote women vets' interests, was no longer necessary.