As long as the front and rear number plates are displayed and visible on the front and rear of the car you are fine, they don't have to be in any particular spot on the frot bumper, hence why when ppl have bike racks on the back that cover the number plate they just put a bit of paper with it written on it somewhere visible and don't get pulled up for not displaying their actual number plate. So if you took it to court I imagine you would be able to get rid of the fine
Don't swear by this it's just my impression as I got pulled up for the same thing while getting defected in my old 180 and the cop said it at least needed to be some where visible rather than just not there at all, having said all of this I didn't go to court with it because I had a number of other fines that went along with it that I couldn't fight so all in all this could just be the opinion of someone who has never had a good expirence with cops and not actually be correct