Customer refunds on account

Hi All

I have a question, why on earth can we not part refund a customer credit note.

I have a client where the situation is highly complex. He's in the building trade and as such some of his clients keep a retention. Which is fine. However, one of his clients had a VAT inspection and was told that my client had invoiced them incorrectly with the wrong VAT codes applied - mainly because they didn't tell him the full story in the first place. 

Now his client is very good at keeping the retainer, and never paying, but obviously as a result of us having to reissue the invoices for his client we asked that he only pay what was actually owed to them, i.e. the VAT minus any retainers that they still owed him over several years of work; he agreed to do this. He part paid them a bulk amount saying that he would pay the rest once they had agreed what the retainer amount should be, but they basically bullied him into paying what they believed they were owed for the VAT. He paid the balance.

As far as the system is concerned, we've pretty much sorted out where we should be. However, we can't now reconcile off the 2 bank transactions because a) Sage won't allow part refunds to be allocated against credit notes in 'refund client' (why not??????); b) we can't even make an 'other payment' to a client account in order to set off that refund against it and then allocate to the credit notes in the client account itself or c) we can't set up a refund to cover most of the credit notes, use match in the bank feed and make an adjustment as we can't post directly to the debtors account. 

Please can someone help, this client is useless at making payments on time and correctly and this whole process above has made it even more difficult as there appears to be no solution we can use in order to allocate the refunds against the credit notes. We really need to get the client account sorted so that we at least know where we're at, even if our clients client doesn't. 

Thanks for any help in advance,