Another VRT question.

Hi, I would like to find out whether anyone can tell me roughly what I could expect to pay in VRT on a 1998 BMW 735i from Japan ? I have searched high and low, and as many people have discovered, there is no entry for a 1998 735 on the VRT calculator. I don't believe that there were never any 735's in the country so I am not sure where to turn now.
I found an emissions website, which lists the NOx figure of 85 mg/km, this for a 2001 E38 735i.
If I look under "First registered in Japan" then there is no entry for any 7 series, but if I look under "Not registered in Japan" I can only find an entry for an E32 735i, so I am assuming that this is the same car but with an incorrect entry. The VRT would seem to be about right, €1420, compared to other cars that I have imported in the past. But I have never imported a BMW. I also see that there are no entries for older X5's either. So if you wanted to import an X5 4.4 then you have no idea how much VRT you will be billed for.
Perhaps someone may have some advice ?
Pierre3.