Vies query re invoice basis

[ninak]

Hi, this is a really basic question, sorry, but I want to double check something. We provide an internet based service to another EU country and have started making VIES returns. We charge for this monthly, issuing an invoice each month for the previous months service. The vies return is not based on a cash received basis. My question is whether it is the date of the invoice issued that dictates which quarterly return it goes into or is it the date the service provided?
For example, we issue the invoice for the March bill in April. Does this transaction go into the first quarterly return or the second? I am presuming the second, but want to double check.
Thanks in advance.

 

[ninak]

Just got off the phone to revenue who have told me that it does not matter whether I put it through under the month the service was provided or the month the invoice issued. I can pick which ever suits according to them!