Complex sentence: Hunter's "colossal work" on the dictionary took up seventeen years of his life: seven years on his own, and then ten years working with the team of Henry Scherren and John Williams at Forest Retreat, Hunter's house in Loughton, Essex.
Split into simpler sentences: Hunter's "colossal work" on the dictionary took up seventeen years of his life: seven years on his own, and then ten years working with Henry Scherren and John Williams. The team worked at Forest Retreat, Hunter's house in Loughton, Essex.