Here is my take,
Step 1: Enter the full invoice as you would to any vendor invoice ensuring you have all the supporting documents.
Step 2: Go to Pay Bills and clear the bill as if the business paid for it.
Step 3: Claim your money from the business by using the Transfer Funds functionality (see screenshot) to debit your Directors Loan account. ( Dr Directors Loan account & Cr Cash at Bank Account). Description: Being a claim for a business expense paid for using a personal account.
This will clear it without any drama and all entries will be valid.