Cormorant back (Phalacrocorax carbo)

Adult Cormorant from the back, with the water rolling off those lovely feathers.
The pair I've watched all year have had no special marks on their heads like these, and I can find no mention of them having a 'winter/summer plumage' per say.

Although these are not the most spectacular photos, I wanted to post this for a couple reasons.
One being I'd like an ID on the type of Cormorant this actually is. I've looked and looked through miles of sites and photos and although he looks a lot like a double-crested cormorant, he also does not. (no white on the breast).
Secondly there has been a pair of cormorants staying near the Shorden reservoir at Alexandra for over a year now, and if this happens to be the same ones in winter plumage, the family was out and about.
I counted one adult and 4 young the day I took these.