1. Landlord underpayment
Go to Lettings Properties > Property balances and click the value showing under Landlord balance.
On the left sidebar, click on View bank lines.
Locate the Manual rent out line related to this payment.
Click the ID number and split this bank line into the amount physically paid and the remainder.
For the balance paid, set the Category to the property and Subcategory to Rent out.
For the remainder, set the Category to Business and Subcategory to Ignore this bank line.
Click Add lines above.
Go to Financials > Unassigned lines, and it will now be possible to match the payment out.
The extra balance still owed will show on the landlord's balance as available to pay during the next payment run.
2. Contractor underpayment
Go to Bank > View bank lines.
Locate the Manual Landlord Expense that pertains to this payment (it should have the same reference as the payment out).
Click the ID number and split this bank line into the amount physically paid and the remainder.
Assign each of these with the Category set to the property and Subcategory to Landlord expense.
Click Add lines above.
Go to Financials > Unassigned lines, and it will now be possible to match the payment out.
Manually pay the remaining balance to the contractor from the client account.
When this part of the payment clears, it will be able to be matched as usual.