There is absolutely no requirement that you change your name.

Pretty much what it says. They are doing their final review and soon you will receive a written notification telling you of their decision. If...

Real debt collectors send written notices rather than leave messages on the phone.

Somebody is trespassing on your property. Call the police.

Agreed. Never talk to the cops without a lawyer by your side.

I do not see a question here and certainly not one that could be answered by attorneys in the US. You will have to reach out to counsel in the UK...

In a word, no. Thankfully your grandson was not injured so there are no damages and thus no claims.

That depends on whose name is on the title as opposed to who is on the loan. Anyone whose name is on the title is an owner with full rights to...

You will likely have better results by picking up the phone and making some calls.

Only your lawyer knows for sure so you will have to ask them.