All these cars had plates on standard UK formats, but none are UK numbers. Can you help? they are:
SBV 30 Z, FU 319 A, Z 00 32, ILL 1702, HHO 47024, CA 41041, BJ 23674 and 529 439. CAR 07 was also seen, but had a foreign band, but illegible. 399 SU 1454 just seen on small (Japanese size) UK plates. May just be Japanese import (forgot exact style) but jury still out on format. They are also on my website (see my details).

UPDATES It turns out most are foreign plates made on UK blanks. Two are fakes.(BJ ZX 97, MSO 4778). FU 382 R is a genuine German import plate parked near me, so the other FU is probably a remake (from Furth). Z-00-32 would be a Dutch trade plate, so Z OO 32 on UK style ought to be the same. N 042965 is a German new style plate, similar to HH above. Two letters plus 5 numbers is a Danish and Norwegian format and many more. One by one, they are worked out.

Update#2 ZOO 32 seen again a year later, Dutch Z plates are only valid about a week, so probably to the fakes list. 399 SU 9454 is a Japanese import, as I have seen many since, as some plate makers here can't tell how to translate plates in full. I have (I am told) the only known picture of one of these which spells out YOKOHAMA in full as well, instead of the correct abbreviation, KNY, and seen Kawasaki and Izumi written in the same fashion.
I have now about 30 of these, some identified since, including a selection of photos. Sadly, the year-long London congestion charge has coincided with a huge arrival of clearly faked plates that do not fit any format in the world. See my plate collection here if you want to see rare and non-official examples.

Update #3 Thanks to the Rac www.rac.co.uk now giving a number plate lookup service for UK numbers (register free to use it), I've eliminated a few more. The Mazda Van in Surrey BJ 23674 which I have seen again since, is Northern Ireland reg BJZ 3674, with the Z made into a 2, and the 2 being moved to the numbers group. I also found one not added here, which I guessed was the case, 0052500, which was really OO 52 SOO, the S was changed to a 5 and the gaps had been removed between the groups. Any tweaked genuine UK plates can now be confirmed at the click of a mouse. Now, if I could find the same sites for all the other countries as well...

529 439
six numerals are standard issue in the Northern Territory
http://www.ozplates.info/home_oz.htm

Could they be diplomatic plates?

maybe you'll have more luck with this page .. I found zilch
www.olavsplates.com/country_index.html

diplomatic plates:
www.dreamwater.net/scsonka/diplolicpl.html

BJ ZX 97 looks like a Dutch license plate number, but for regular cars no plates are issued starting with B. It could very well be the number of a Dutch lorry though...

I thought it looked Dutch, but luckily this one is in my road, and the owner said he'd remade it from Belgian plates. I don't remember 4 letters on them though, so my fake plate theory is looking likely, probably for 90% of them. Especially as it's right hand drive. And even Belgians have road tax discs! (he didn't).

Though missing this week, my Europlates book (old edition) had little joy even getting a close match to these. UK diplomatic plates are very obvious, and most European ones are identifiable. See my other replies for more.

Yes, it's Olav who I start with, plus I'm waiting for the 2003 Europlates book to come out as well but I'll check out your site now and hope I get lucky!

Up to top for update and picture link added.