Chat Danger
ChildNet
http://www.childnet.com/kia/parents/
Get Safe Online
Sections on protecting yourself, your computer and more importantly your children
SaferInternet
https://www.saferinternet.org.uk/advice-centre/parents-and-carers
ThinkUKnow
https://www.thinkuknow.co.uk/parents/
Lots of advice for parents of children of different ages