So.......
I've found the part that I need and can get it from America via ebay.
At the same time I rang the local stealer who by 4.30pm tonight couldn't work out what the part was I wanted from my VIN. So I gave them the part number and they are going to have to speak with those in Japan again to verify it is suitable for my car (I already know it is), then get me a price. Anything from 70-130 plus VAT.
Ebay option from USA looks cheaper, even with import duty, and it's still the same official part.
The USA ebay merchant gave me this great link too - if you ever want part numbers, including for JDM cars, just bookmark this! They certainly have customer service licked over there - fantastic!!
https://partsouq.com/