Hi All

I found the solution for this. I am not quite clear on the theory but it seems to have had to do with the base currency. My main currency is ZAR. The reports seem to have been working out the values based on a calculation of the main currency to some other currency. I had to change the main currency ZAR to a current rate of 1.0 (this meant that the invoices going forward were correct in the report) then I had to change the previously recorded rate to another value (in my case 24.66054) which forced the existing values to match the actual invoice values

Hope that someone else finds this useful