Sorry for the delayed response - you were right in that the fields in question were the wrong data type,changing them fixed the issue but forgot to reply and thank you.
I was hoping you'd be able to help me with an amendment to the VBA i was trying to do - I'd like to also grab the field 'Installment Description' from the source table and populate the field in the output - i made some amendments which worked. However in doing so i broke the way 'Installment amount' was being populated. I've gone over the code several times but cant see what could be causing these differences logically.