Michael Cochrane and Frank Windsor had both previously appeared in Doctor Who alongside Peter Davison ; Cochrane as Charles Cranleigh in Black Orchid in Season 19 .
Windsor played Ranulf in The King 's Demons in Season 20 .
Michael Cochrane and Frank Windsor had both previously appeared in Doctor Who alongside Peter Davison ; Cochrane as Charles Cranleigh in Black Orchid in Season 19 , while Windsor played Ranulf in The King 's Demons in Season 20 .