Q57: My ex partner has got access rights over our child but my son/daughter has to be back by 1600hrs and he/she has not brought my son/daughter back yet, what can I do?
This is family law and as such the police have no jurisdiction over the matter. You need to seek further advice from your solicitor. It is likely that the case will go back before the court, who will decide what course of action to take.
See also the web app provided by the Department for Work and Pensions 'Sorting out separation' and the Citizens Advice Bureau's website (links in related information).