How to reset forgotten Restrictions password with iPhone restore?

Hi,

I set restrictions on my iphone to disable in-app purchases so that my children don't rack up a bill on my account. Unfortunately I've forgotten the password and now I need an in-app purchase for CoPilot navigation app.

Can I reset my iPhone and then restore from a backup to clear the restrictions password? If so, is there a step by step guide to do this? Much appreciate any help.

Boz