Chromdesign grille screw question

[Anonymous]

I've just fitted the rear Chromdesign grille, but when I've come to put it all back together, I realised that the screws for the number plate are no longer long enough.  The grille sits quite a bit further forward than the stock plastic one, and as a result the screws are about half the length that they need to be...  Has anyone else had this problem? Anyone know what type of screw they are (the thread looks different to a normal screw) and where I could get some longer ones?  

I'm intending to re-attach the number plate without the plastic backing plate by drilling a couple of holes in it - is there any reason why I shouldn't do this?!