I know no one can say for sure but would this concern you?

[Juststandup]

A three year old (just turned 3 if relevant.)

Harms himself - bangs head on things in frustration.

Very destructive, wrestles / pins down other children, hits them with toys without provocstion.

Doesnt eat very healthily, no fruit or veg.

Throws things all the time.

Just wondering if this is normal if extreme?

The eating no, the rest yes

No, occasionally it’s ok but as a regular behavior - not.

I wonder if @VisionsOfSplendour answerd the question for the title : would this concern you ?
Whereas I answered the one for the post : if this is normal?
to add to my comment: it would concern me very much.

Of it's a regular thing then I'd want to get them assessed by a professional. Are they at nursery?

It may be concerning and may not. What we need is the rest of the picture, as in how do you manage this? What do you do when he displays this behaviour?

The part about eating no fruit or veg is bad. Very poor. The other behaviour is probably normal, but should be managed, otherwise the kid will find that nobody wants to play with him (and their mums won't invite him to play)

Is the 3yr old mostly offered high sugar content foods, or do they have a wide offer of fruit & veg they just ignore those & select plain toast, pasta, chips, milk, bacon instead ?

Life is frustrating when you're 3. I understand a frustrated 3yr old, but not one who has full control of their own food supply.