Complex sentence: Lavandin was sent to England for the Derby at Epsom, with the Australian Rae Johnstone taking over as his rider, becoming Wertheimer's first runner in the race after more than forty years of involvement in the sport.
Split into simpler sentences: Lavandin was sent to England for the Derby at Epsom, with the Australian Rae Johnstone taking over as his rider. The colt became Wertheimer's first runner in the race after more than forty years of involvement in the sport.