Help on importing car from UK

I'm purchasing a UK reg car which has been in Ireland for over a year already.
The guy i'm buying it off has a UK license etc.

My question is - when it comes to me clearing it - i need certain documentation. I've gone through the list and i'll have everything, however point number 6 has me stumped:

For vehicles imported from Northern Ireland, where the invoice is dated more that 30 days earlier than the date the vehicle is presented for registration, details of where the vehicle was stored. For vehicles purchased in the EU, we require shipping details to confirm the date of arrival of the vehicle in the state. For vehicles outside the EU, we require the single administrative number and the date it was issued by customs at the point of entry to the EU.

How do i provide something like that for a vehicle that's already been here for over a year - but on UK plates??

Confused.