Brits code the year of the manufacture of the car and which half of the year it was first registered in the license plates, which stay with the vehicle for the life of the car. Wikipedia has a great article at:
http://en.wikipedia.org/wiki/Vehicle_registration_plates_of_the_United_Kingdom#Year_identifiers
55 or 57 plates would translate to a 2005 or 2007 vehicle, first registered in the fall or winter.
I had a software contract once with the company that's behind Carfax, RL Polk, and did some VIN work for them....as well as being ex-GM and ex-EDS.
BTW, there's a really fun Brit site,
http://fordtransit.org
that has a Transit Connect forum that's amazing:
http://fordtransit.org/forum/viewforum.php?f=54
These guys have had the Connect for almost 10 years - you can almost see our trucks' futures by looking at it.
cheers, as they say.