CIS Tax suffered

Hi,

Has anyone had any joy recently in getting HMRC to provide details of any self-employed subcontractor's income and tax deducted to include on their tax return?

I know that over the last couple of years they have demanded that the subcontractor contact all of his contractors to provide details and also provide evidence of trying to ascertain the information this way.

A new client of mine has 6 years worth of returns to be submitted, has no recollection as to whom he has worked for in this period and in addition has no bank account in place. He was paid sometimes in cash and when by cheque has paid it into a family members bank account.

Has anyone had any joy in getting this information from HMRC recently?

Thanks

Matt