Complex sentence: He was interested in building things with model house kits, Meccano and cardboard; an early gift of a Hornby train from his mother started him on his lifelong love of trains.
Split into simpler sentences: He was interested in building things with model house kits, Meccano and cardboard, and eventually in model railways. An early gift of a Hornby train from his mother started him on his lifelong love of trains.