Complex sentence: At the time the sweet was re-branded under the Maynard's banner, the black Midget Gems were changed from liquorice flavour to blackcurrant, but only in the bagged product-those sold loose, from jars and boxes, remain liquorice.
Split into simpler sentences: At the time the sweet was re-branded under the Maynard's banner, the black Midget Gems were changed from liquorice flavour to blackcurrant, but only in the bagged product. Those sold loose, from jars and boxes, remain liquorice.