One of the local identifiers for registrations in that area is *OO, and the local vehicle licensing office release registration numbers in batches so Ford can't make all their press cars WOO or their Cosworths BOO - it purely depends on what sequence is in use at that time.

I have an XR4i that is YOO, and my XR4x4 donor was XOO. Nothing special about either of them at all and it doesn't even necessarily signify that FoMoCo was the original owner (though there is a very high likelihood that they were, but most would be staff or management cars rather than anything "exotic").