So he's watching your comings (no pun) and goings, flashing at his window and walking round your garden naked.
I think you need to report everything, for your wife's sake especially (or any woman's, really), as he could well be a little "focused" on her, shall we say. He doesn't sound like a harmless crank to me, and maybe you'll be doing his new neighbours a favour, they might not be as well-equipped to protect themselves as you two are. For all you know, he may well have other offences on his record.
Mark my words, if he stays put and nothing is done, your wife will open the curtains one morning and he'll be on the other side of the window pulling his pud, or breaking in and stealing her underwear, or making "silent" phone calls etc. At least if the Police are aware, if the worst does happen and he does something while she's home on her own, she'll be able to get them to respond immediately. It's a bit of a concern what he is up to when you
*don't* see him or catch him on film. Looking you up online? Going through your bins? Taking photos through the windows and lining his bedroom with them? Could be almost anything.