harassed my wife into moving her car
when you say 'harassed' - what do you mean?
Was he threatening? Intimidating?
Was she frightened?
He was aggressive
details
Now this is the really crucial part he made my wife leave my 3 year old daughter sat on the wall outside while she moved the car
How did he make her leave the 3 yr old sat on the wall - I really don't get this.
Did he not allow your wife to put your daughter in the car?
Did he somehow get between your wife and daughter and threaten your wife in some way if she moved your daughter?
I was of course furious and ready to storm round and give him a few choice words Totally get this - I would be too, however upon reflection and after calming down, I'd realise that my wife is a grown separate human being who does not need me to step in. She's not a child.
my wife begged me not to go confront
and here is your answer as to what you should do. Your wife, the grown woman, has made it very clear. You may not agree but it's her decision. Unless of course, he threatened her or your child etc. And if that is the case, then I'd be calling the non emergency police number as that is absolutely not acceptable,
AIBU to want to go explain exactly why he should not come and be rude to my wife while she’s alone with the kids?
Yes, YABU
If I saw the neighbour I would probably say something - oh, by the way, my wife asked me not to come and speak with you about the parking incident the other day, so I didn't as it's her decision. I do want you to know, however, that we can all park where we like. If there's an unsaid agreement that we park in front of our own homes, then maybe it would have been more civil and neighbourly to explain that rather than being a complete twat and speaking that way to anyone, let alone a woman on her own with her child. If we have to park in front of your house, it is what it is. We won't be moving the car again so don't ask.
PS you seem like a decent person. It's the 21st century. Empower your wife.