Stolen car check / Help

[Glen-Japan]

Hi, I'm new on this site and looking for some help. Basically I can purchase an NA1 from a good friend that bought it many years ago without documents. He stored it in a barn for nearly 15 years. I'm trying to check if it's a stolen car. I don't think it'll come up on the standard HPI check as its a Japanese car and never exported, it is at present in Japan where I live. You might think its easy to check here! but it seems to be impossible, too long ago even if it is a stolen. If I can confirm its all clear then I will export to UK to keep or sell later, not sure yet. I have run it through the NSX Prime check and that seems Ok except you need a full 17 digit and Japanese cars only have 7 digit chassis number not a Vin number. I made the chassis number using an online decoder which gave me these number: (JH4NA1252MT) then added my chassis number 1004xx So its a 1991 3.0L auto. The chassis number on the plate is NA1-1004xxx [Edit: Kaz-kzukNA1; for security reason, hidden the last 3digits.]
Ok, so if anyone can run a full European check or send me a link to do it that would be great, if Im unable to get any info then he's going to scrap it for parts!! One other thing I have thought of even if it does turn out to be a stolen car its not the end of the world as the value that was more than likely paid out 15 years ago would not have been very much.
Thank you.
Glen.