I have just started to pursue payment of SM through courts and I was passed from pillar to post by County and Magistrates Courts. Nobody seemed to know what I should do. Finally got it sorted (I hope and pray) and had to complete form D151 to register the order with magistrates for future payments and to collect 5 months arrears. The form needed to be submitted to the County Court where the order was made and they transferred it to a central collections division who are currently writing him a 14 day payment letter, and will then issue a summons for him to appear before magistrates.
Hope that helps.
The easiest way to enforce an order for maintenance if you don''t have a solicitor is to register it with the magistrates court and apply
for an attachment of earnings (assuming the payer is PAYE.) County Court judges are legally trained and have more powers than magistrates so County Courts deal with more complicated cases, although not all types of maintenance enforcement is available through the County Courts.
You need permission from the court to apply to enforce maintenance arrears of more than 12 months.