Wine Equalisation Tax: calculation of credit for WET paid on wine that is exported

they have become liable to WET on an assessable dealing with the wine (the WET for which they have become liable is not counted to the extent to which it has been the basis of a WET credit entitlement), or 2. they purchased wine for a price that included WET (the amount of WET borne is reduced by an amount of WET included in that price that has been refunded or an amount of WET that has been credited to them).