If I create a payslip with a past date that hasn’t been allocated a payment, it doesn’t show up in the Employee Clearing Account - so I don’t know which payslips are still outstanding. Am I missing something?
Payments are not allocated to payslips themselves. Payments are allocated only to the Employee clearing account and the individual employee’s subsidiary ledger. You can drill down to that ledger, but you will see only debits and credits applied to it. Payslips are credited; payments are debited. The difference is what you currently owe the employee.
What I’m battling to understand though is the following:
If I create 3 payslips:
- Date: 01/11/2017 - $200
- Date: 01/01/2018 - $200
- Date: 01/01/2018 - $200
Only the upcoming payslips 2 and 3 ($400) will show in the Employee clearing account, even though payslip 1 hasn’t been paid yet. This then means my balance sheet on the summary page doesn’t reflect the true amount still outstanding
Your situation cannot be understood without seeing the Edit screens for all three payslips, a listing of the drill-down reports on affected employees from the Employee clearing account, and the Edit screens for any related payments.
I am also curious why you say only payslips #2 and #3 show in Employee clearing account. They are both for next year and should be ignored by Manager until their issue dates arrive. So whatever you are seeing there is from some other payslip(s), not from those.
I found the issue. I had set the start date to this month, and then set up test payslips for the previous month. All sorted now 
Thanks so much for your help, really appreciate it.