Complex sentence: Over 200 Scouts from across London, led by the Enfield District Scout Band, took part in the 2007 Parade, heralding the start of the UK's "2007 Centenary of Scouting Celebrations".
Split into simpler sentences: Over 200 Scouts from across London took part in the 2007 Parade. They started the UK's "2007 Centenary of Scouting Celebrations".