Hi Guys,
Kev, you are almost correct mate, but if I may just put you straight on a few points.
The registration number as shown is of the UK layout but, if it is absolutely correct certainly not a UK registration, as we have no '50' registrations. As Kev has correctly stated already, in the format (say) HX 04 EET, the HX state the region, the 04 indicates the year of registration and the EET would be unique to that particular vehicle.
The puzzle Eugene is the middle 50 of your stated number. Could this actually be 52 and not 50? The thing is that (again as stated by Kev) every 6 months the number changes from '0' something, like 02, to '5' something like 52. The whole '0' numbers run from 1st March to 31st August each year, with the '5' numbers running from 1st September to 28th (or 29th February).
Previously all UK cars had (from 1962) either letter suffix or (from 1983) a letter prefix, with the latter changing ever year on the 1st August. There is further complication in that to try to make the 51 reg (from 1st Sept 01) earlier year suffixes were changed every six months as well - thus a UK T reg (prefix) was from March 99 to end Aug 99, with V-reg from Sept 99 to Mar 00, and so on. The last UK suffix was a Y-reg, which ran from Mar 01 until end Aug 01. We didn't have an 01 reg Kev, the first in the new style was 51, as it was the end of 2001.
Another confusion is that (say) 53 covers the end of 2003 and the start of 2004 - so if Eugene's Yaris is indeed a 52 reg and not a 50 as stated, then it could conceivably be a 2003, but would certainly be at worst a late 2002.
It's all rather confusing, and most buyers try to purchase a new car on a '0-something' plate so that their mate's know that they have just brought a new car!
We are currently on 08 reg
Hope this helps