Complex sentence: Ultimately the race was cancelled in 2005 and 2006 as safety issues could not be resolved with the local authorities, in particular the police, who proposed a new route via Dinnington (which was met with much resistance from the current organisers).
Split into simpler sentences: Ultimately the race was cancelled in 2005 and 2006 as safety issues could not be resolved with the local authorities. In particular the police, who proposed a new route via Dinnington (which was met with much resistance from the current organisers).