On the first monthly return in May 2007, will the paper and online returns be pre-populated from information held in the old system?
For paper returns the answer is yes. If you use the free HMRC Online Return and Forms CIS service then HMRC will pre-populate the list of subcontractors from information held on the old system. If you use commercial software to file online then you should contact your software vendor for more information but in many cases the monthly return will be populated with information directly from your own accounting and payroll software.