Xero Payroll EYU

I have recently taken on two new bookkeeping clients who were taking care of their payroll themselves. They have made some mistakes while using the Xero payroll software, and it needs updating for the previous year. I don't claim to be a payroll expert, so would be great if I could Skype and screen share with someone to sort these out. Ensure they are on the correct codes going forward, and then help to amend the previous tax year information. Please let me know what your experience is with payroll, and specifically payroll in Xero. Thank you. Abi