mdkv5

Posting this as an fyi for anyone that has to get this number. It's on the underside of the hood on a label that looks like this. Took me a couple of hours to find and even the dealer had no clue what "Engine family number" is...
I'm pretty sure this is what is referred to as the EPA sticker, please correct me if I'm wrong.

AoA asks for this to issue a Certificate of Conformity which is needed for importing the car into the states.

Tman007

Good to know, for those that have lost their manuals.

If you do have the manuals that came with the car, you can find this number on the inside cover of the "Warranty & Maintenance" booklet. That list contains around 50 or so identifier codes for all the major components and options on the car.