It seems to be par for the course with these.

I don't think i'd even drive it over here until it was mapped for UK fuel. I was fortunate with my STi Type R in that it was imported from new and mapped for 98RON back in the day.

Give API a bell and they'll take you through the options. Can also source brand new closed decks from Japan. That's what the previous owner stuck in mine about 10k miles ago.

All the best with getting it sorted.

JK