The spirit of the law is that one needs to be displayed. The wording is old and no doubt the intention was that vehicles need to have one in a position fixed as per the makers plinth. Type approval says it all.
Al is spot on. There was a show GTI stolen recently that ran no front plate, i wonder if this was picked up by the cameras.
@dombacon if you were stopped, a commons sense approach probably would be taken. Ultimately it's a £100 ticket or court. In your case I don't think it would be in the public interest to prosecute, but of course I'm not the deciding people.
@George10 traffic police would though :p