James, you could try the below:

SELECT *
FROM SOPInvoiceCredit
INNER JOIN SOPInvoiceCreditLine ON SOPInvoiceCreditLine.SOPInvoiceCreditID = SOPInvoiceCredit.SOPInvoiceCreditID
INNER JOIN SOPOrderReturnLine ON SOPOrderReturnLine.SOPOrderReturnLineID = SOPInvoiceCreditLine.SOPOrderReturnLineID
INNER JOIN SLCustomerAccount ON SLCustomerAccount.SLCustomerAccountID = SOPInvoiceCredit.CustomerID
INNER JOIN SOPStandardItemLink ON SOPStandardItemLink.SOPOrderReturnLineID = SOPOrderReturnLine.SOPOrderReturnLineID
INNER JOIN StockItem ON StockItem.ItemID = SOPStandardItemLink.ItemID

Not the neatest but would allow filtering on Items & Customer in a period

You don't need SOPOrderReturnLine in that query:

FROM SOPInvoiceCredit INNER JOIN
 SLCustomerAccount ON SOPInvoiceCredit.CustomerID = SLCustomerAccount.SLCustomerAccountID INNER JOIN
 SOPInvoiceCreditLine ON SOPInvoiceCreditLine.SOPInvoiceCreditID = SOPInvoiceCredit.SOPInvoiceCreditID INNER JOIN
 SOPStandardItemLink ON SOPInvoiceCreditLine.SOPOrderReturnLineID = SOPStandardItemLink.SOPOrderReturnLineID INNER JOIN 
 StockItem ON StockItem.ItemID = SOPStandardItemLink.ItemID

You may not need StockItem either as SOPInvoiceCreditLine has ItemCode and ItemName.

You will (probably) need to filter on "SOPInvoiceCredit.SOPInvoiceCreditTypeID = 0" (Invoices only) and "SOPInvoiceCredit.DocumentStatusID =2)"  (completed)

You don't need SOPOrderReturnLine in that query:

FROM SOPInvoiceCredit INNER JOIN
 SLCustomerAccount ON SOPInvoiceCredit.CustomerID = SLCustomerAccount.SLCustomerAccountID INNER JOIN
 SOPInvoiceCreditLine ON SOPInvoiceCreditLine.SOPInvoiceCreditID = SOPInvoiceCredit.SOPInvoiceCreditID INNER JOIN
 SOPStandardItemLink ON SOPInvoiceCreditLine.SOPOrderReturnLineID = SOPStandardItemLink.SOPOrderReturnLineID INNER JOIN 
 StockItem ON StockItem.ItemID = SOPStandardItemLink.ItemID

You may not need StockItem either as SOPInvoiceCreditLine has ItemCode and ItemName.

You will (probably) need to filter on "SOPInvoiceCredit.SOPInvoiceCreditTypeID = 0" (Invoices only) and "SOPInvoiceCredit.DocumentStatusID =2)"  (completed)

How would i attach a customers order no like > invoice number | customers order no | vat price