Jaghebby

My sister in law replaced her headlight units on her 2011? Polo.The units she fitted take H7 bulbs (single filament) where as the originals took H4 bubs (2 filament). This means when she puts on full beam the dipped element goes off! Is there an easy workaround or will she need to replace the headlight units for the correct part e.g one that take H4 bulbs? Any advice would be appreciated.