Well checked Fishbee bvut the small print says This really fast grower is a great choice for summer and autumn leeks. Plenty of lovely long shanks, some up to 60cm/24in long, which cook well and have a good flavour.
So it is for sowing March indoors, April outdoors and harvesting before winter, therefore harvests from planting now will be small as its long stems probably won’t survive much frost.