hey, just stumbled on to this topic now...
The prices mentioned here seem quite high..
I have a friend here in England who has just started a business making these plates.
i've not bought from him as i don't have a car here, but AFAIK his are only 10 Pounds for a set.
quality is good, but they are the Plastic style ones that they have in the UK, not metal...
Have a look if you like, and If you're interested I can see if he'd be able to give a discount for a group buy...
this is his website - http://www.platewerx.co.uk/