It was not made in any way, it was just exchange rate entered in “Exchange Rates” tab.
It has paid the right amount in EUR, but due to changes in rate, amount that was received in GBP was not the same as it is on invoice due to rate used by bank (in most cases).
Yes, I need to write of this. My usual way of solving is journal:
CR Receivables | Customer X,-
DR Currency loss/gain X,-
What would be your suggestion do this in Manager?