Most British historians. They would prefer "Early Medieval Period" (c. 410 - 1066), spanning from the Rescript of Honorius to the Battles of Stamford Bridge (ending the Viking era) and Hastings (beginning the Norman period).
Within "Early Medieval England," they will eschew the term "Dark Ages" and instead you will talk about specific eras such as "Sub-Roman Britain" (c. 410 - 597), "Anglo-Saxon England" (c. 449 - 1066), "Viking-era Britain" (c. 793 - 1066), or even "Anglo-Danish England" (c. 991-1016).
Within "Early Medieval England," they will eschew the term "Dark Ages" and instead you will talk about specific eras such as "Sub-Roman Britain" (c. 410 - 597), "Anglo-Saxon England" (c. 449 - 1066), "Viking-era Britain" (c. 793 - 1066), or even "Anglo-Danish England" (c. 991-1016).