Tried that but it's still not allowing me to match up the total transaction for that day. Picture attached shows the transactions from the day I'm trying to match. Seems pretty impossible to pull in a negative value but I need -£102 refund to be able to make up the correct amount.

Not sure if I should be using the resolve/difference toggle and entering the payment to the customer in this way (but I would imagine that would require entering just a credit note to begin with - doesn't seem like it would be the right way to do things).