ello Dave, glad to hear you have healthy lizard site in your neck of the woods but just because they are there doesnt mean there WILL be Adders, however the chances are good as Devon is certainly a good spot for these beautifull creatures. I find coming across a spieces your not sure exist on a particular site so special, so keep looking, and keep us posted. Dont forget to take care and enjoy.
ps, get out sooner rather than later , with the new ferns and grass coming through they will become a lot harder to find.