Normally, you have one month and seven days to submit your VAT return if you file it electronically. As your VAT return is dated 28th February 2013, you have until 7th April 2013 to file it with HMRC.
However, HMRC's VAT online service will be unavailable between 6.00am 4th April and 6.00am 6th April 2013. So I would encourage you to submit your VAT return early by 4th April 2013.
Remember, late VAT returns may be subject to surcharges.
Your local TaxAssist Accountant would be happy to help you manage your VAT affairs. Contact us for more information and to be put in touch with your local office.