Car in repair for over 8 months - Communication stopped from garage

Hetz

So bit of background - my car developed a fault in December 2022 and was handed to the garage in December 2022. 

Now Ive been told it has engine damage and would need a engine build - so I told them to carry on with work - at that time I was told the car would be ready in a few weeks due to the work involved. Since the car left my premises - it was trailered away I have not seen the car or have any photos etc of any work on the car as promised from the garage. 

March - I ask for an update with the car, I was told it is being worked on. 

Forward to April - I started chasing the garage to what's happening with my car, I was told via text that nothing to worry about its being done. 

May - Again I ask and i'm told its a big job and he's waiting on parts and the engine is still at machine shop 

June - I ask again, same story.......

July - Im now getting frustrated with the situation, I ask again, again im told the same story.... alarm bells are now ringing as to what is actually going on? 

So naturally being frustrated - I explained he has had adequate time with the car and if he can't repair the car I would like it back. 

Now he has stopped answering any calls or text's. 

Now the issue I have is, he moved premises since he took the work on, so I have no idea where my car is or what state it is in? I only have his contact number and his home address. 
Since having my car I was promised pictures of the work etc... you guessed it nothing. 

Now where do I stand with the situation? I can't get hold of him and i'm concerned if he still has my car or not?

Wonka_2

Bit more info needed for people to help

Presumably given the latter parts of the post this is an independent so it's not a new-ish, in warranty car from a main dealer ?

Is it something special/with some value and is he a specialist in this area ? 
Does (or did) he have any premises ?
Any social media/car forums footprint ?
Registered on Companies House ?

If you genuinely can't find him then report it as stolen but be prepared to answer questions on why so long ? And on this basis hopefully it's still insured ?