"Brides..." definitely has an air of kink to it, moreso than most of the other films produced by Hammer with a male bloodsucker in the lead. Early drafts of the script supposedly alluded directly to Dracula himself as Meinster's "initiator". When you take into account the Baroness's horror at her son's wayward ways, there's a tacit implication there. Peel's casting just strikes me as perhaps a veiled decision to take the Dracula series in a different direction that just wasn't popular at that time. The sapphic vamps of "The Vampire Lovers" and "Lust For A Vampire" would become prevalent years later, but similar ambiguity toward the male of the species stayed pretty under the radar.
"Breaking away with the beast of both worlds, a smile that you can't disguise..."