Hi, your IP will normally correspond with you and inform you what you need to collate and send. I send in payslips quarterly but still send P60, evidence of any increased expenditure (if it's high) and a revised income and expenditure form.
If they've not let you now what they require why not drop them an email.
IVA final payment left the bank on the 26th January 2013...looking forward to a debt free future.
You would need to send in all of your wageslips received over the last year, together with a revised income and expenditure summary and details of any significantly higher expenditure you have experienced during the year. Your IP will usually contact you about a month prior to the anniversary to let you know exactly what they need in your specific case.