I suggest you get at least two independent estimates for complete replacement/repair of the door, other than your neighbour, take photographic evidence and always record what happens when and what is said as soon as possible. All this, will be evidence against your bully of a neighbour. Inform him in writing that you are taking legal action against him for trespass and damage and that you will record any threats with photographic evidence if he comes on your property again. Keep a copy with dates of everything you send him.
I have found that once these type of people walk over you, they will continue for ever unless you show them that you will stop them one way or another. You may get a little respect or he will give you a wide berth in future.
Ask him for his insurer details as he will be covered for any liability through his business. If he refuses to give it to you, report him to the Trading Standards who will also give you further advice and may even act on your behalf. I have found them very helpful as they have even told me what to put in a letter.
What concerns me is your safety now the door is damaged. If your insured, give them a ring and tell them what has happened as this may invalidate your insurance policy if the house is insecure. They should also be able to send someone out to secure your house?
Any additional costs that you have to spend because of the damage, record it and keep all receipts to pass on to your insurers.
If this builder has a company name, inform your insurers of this as they will be able to do a search of their required legal documents.
Please take advice from the C.A.B. also and anyone who is willing to help.
Good luck and I hope you sort him out.