I can also confirm that the last set of images shows a female..
I have been looking at the scale and adder head patterns at a number of sites and over a number of years. My work has been following up on a paper that recognised the possibilities of sexing Adders using images of the Rostral scale and pre-nasal shields. The markings of the individual shown on the last image is very indicative of a female V. berus.
So, along with the sheer size of the animal, the 'stepped' tail, the general colouration, rostral colouration and sub-caudal scale counts it should be really quite straight forward to sex animals in the field. Lots of text on the subjects out there folks, but happy to answer any questions I can.
Kind regards,
Brett