Please take a look at the following websites:
youngminds.org.uk/find-help//parents-guide-to-support-challenging-behaviour-in-children/
www.teenagechallenginbehaviour
www.family-action.org.uk/family-monsters/support/challenging-behaviour/
www.kent.gov.uk/challenging behaviourworkshop/SEND
www.kent.gov.uk/education-and-children/early-help-support-for-families