According to our conversation on phone, there is one concerning issue which is the specified expiry date of BG in the document. By having this, in case that the work of contractor has not been finished by the last date of BG's validity, we would not have any guarantee from the contractor to secure if the contractor will be responsibly for the pending work.
To suggest, please kindly request the contractor for the extension of BG in case that the contractor's work has not been finished by the first expiry date of BG specified in the document.