I have only just realised that you are unable to manually change amounts in the 'Pay Liabilites' screen if a client is short paying or not paying the exact amounts required for any other reason.
This seems to be rather frustrating as there would be a lot of people who would not be able to pay whole amounts owed all the time due to cash flow reasons and who would prefer to part pay.
It would be great if you could manually amend an amount to match what is being paid so it can be deducted from the liability amount properly rather than having to go through spend money which doesn't offset against the liability.
"Ability to change amounts in 'Pay Liabilites' screen"