While I agree Vernon should be punished...severely, I don't think the Kiss was the right choice. Of course, even in canon, Barty Crouch was a ruthless one. It also allows you to introduce Barty Jr, whom we have never heard of before,
Dumbledore's attempt to kidnap arry and force him back into Durzkaban was a nicely worked out bit. I wonder how he found them, though. Harry derailed that with a few well choose words. Ain't it great how magic works?
As always I eagerly await the next posting. Alorkin