As someone who is currently having no luck on dating sites but has been on more dates than I care to imagine I would say that smart casual is best; wear aftershave but do not bathe in it (and use a more subtle variety), no kissing unless a hand or cheek is offered; I personally wouldn't mention spanking unless the venue is a Dungeon or she is wearing a gimp mask; as for your accent, if it is a cut glass upper class accent, do not hide it (if she can't handle that, well, frankly would you want to see her again?), if it is a Norfolk drawl, hide it; as for being widowed, unless the girl she is confident, you may find that the mention of that would be a conversation stopper, although personally, if asked I would say (unless it is something you would rather not discuss in such shallow surroundings which I think anyone would understand); again, if the subject turns to children, say so. There are some women out there who can't abide other people's children too (me included).
Your friend really should have booked you on a speed dating session with people of a similar age group, (I do not know what that age group is, but hopefully your friend would), but as to the rest I cannot comment.
But what do I know? I have a 100% unsuccess rate!!!! Enjoy.