IFRS hardly specify what sort of expenses should be recognized into cost of sales and what should not be taken into cost of sales. It only states the basis of recognizing costs. see that IAS 18.19 reads as follows "Revenue and expenses that relate to the same transaction or other event are recognized simultaneously; this process is commonly referred to as the matching of revenues and expenses"
Therefore it is up to the management to decide whether a particular expense fits into cost of sales or not. In your case you need to decide whether you should include your bank charges inside cost of sales or in general administration overheads or suchlike. If your bank charge is directly attributable to a purchase of a direct raw material, I dont think it is wrong to include it under cost of sales.
Also note 2.11 “The costs of purchase of inventories comprise the purchase price, import duties and other taxes (other than those subsequently recoverable by the entity from the taxing authorities), and transport, handling and other costs directly attributable to the acquisition of finished goods, materials and services. Trade discounts, rebates and other similar items are deducted in determining the costs of purchase”