There are no
Wendy restaurants where I live, so I wouldn't know.
It has lovely
Peter Pan associations, but it is dated. I saw a death notice the other day for a woman born in 1944 whose name was
Wendy Marilyn, or perhaps
Marilyn Wendy; no doubt a very pretty combo in its day.
If you like
Wendy, then you should test-drive
Gwendolen to see if people find
Wendy a natural nn. I suspect they'd mostly if not entirely get stuck on
Gwen, so you'd lose your fave. I'd love to meet a young
Wendy: possibly because of the
Peter Pan character, it seems permanently young, though the
Wendy character does grow up, unlike
Peter!