Possible fix (worked for me):
AAVCHECK and CVCCHECK
In the file class.epdq.php, AAVCHECK and CVCCHECK are all caps, e.g. $_REQUEST(‘AAVCHECK’), however Barclays returns these as AAVCheck and CVCCheck
Changing the request from all caps to to a mix of the specific way in which the parameters are returned creates the exact same SHASIGN, and bobs your uncle… Order Received.
At least for me.