Hi, Jim.
The regulation and the manual are consistent but not the operators, I’m afraid….
You can download the MOT manual from the government site.
https://www.gov.uk/government/public...and-7-vehicles
For your NSX, it’s section 7.3 page 6, 7 and 9 are the key.
Honda garage was correct in stating that your NSX must take BET because your NSX was used on or after 01/Aug/92.
However, failing BET doesn’t become the reason for MOT fail and it’s clearly written in the manual as well.
Once it didn’t pass the BET, then the operator would follow the question shown on the display so not sure why they didn’t follow it or possibly followed it, found the exact match in the database for the specific emission limit for your NSX and then failed it on that basis.
I went through the MOT procedure and the actual description shown on the display at my local Honda garage as my NSX is JDM and I imported it by myself so they required extra support from me.
If you don’t follow the correct flow, you would end up with the wrong criteria. 1st time when they went through, they made the mistake.
One can reject the certificate if the CAT was removed from the vehicle that was fitted as standard but it’s only for the vehicle qualifies for the Full CAT emission test and since your NSX doesn’t belong to that group, removing the CAT doesn’t become the reason for MOT fail.
Hope your friend can help you.
Kaz