Hello again Greg,
I have had a look at DVLA, hoping that would add more clarity. But it didn't !
(A green Alphard. I have not seen one in that colour yet).
The DVLA has the vehicle as first registered in December 2005 (in Japan).
However, the original Gen 1 was discontinued in April 2005; being replaced by a facelifted version.
So I am unsure which version you have. Do you know ?
Is that of any relevance ? Maybe, maybe not !
Whilst not definitive, it is generally believed that the latter model is ULEZ compliant and the former is not; at least officially.
Other members (not necessarily with the hybrid version) have had similar problems.
Hopefully, one of them can enlighten you.