Yes Bubbles, my earlies (Belle de Fontenay) did not flower at all, and only slightly died back - but the spuds underneath are wonderful. I also planted a variety that is a 2nd early come maincrop, has been in since mid-March and I dug up one plant last week and there are plenty of spuds ready there too!
I would recommend that you leave your Desiree in place and start harvesting the others - Desiree can swell to a very large size if conditions are right and you may get a really excellent harvest by leaving them in longer.