So, I've finally got hold of a set OEM mud guards.

Pretty decent condition and will fit them once I finally decide to put my refurbed OEM wheels on.

I have a question about fitting them though.

I bought the guards with the fixings and I have 12 screws/bolts and 12 holes.

So far, so good.

However, on the rear wheel arches I have two holes but three on the mud guard

(the top hole has nothing to line up to on the car).

On the front they match up perfectly but there is some plastic trim of some sort where the guards fit.

My question is; for the fronts do I mount on top of this

"trim" or remove it and replace with the mud guards?
and,
For the rears do I need to drill a hole for the top screw?

(And, incidentally, if the answer to the first question is yes, mount on top of the trim, should there be a similar thing on the rear arches that my car must be missing?)

Cheers.
