I would ignore the existing holes.  Centralise the grille in the hole in the car.... Then mark through the mounting holes into the body.... use any holes that line up and drill new ones as necessary.  You will only need 4 holes - generally two close together at top centre and one in each lower corner (but nor right in the corner..... ther original mounting holes should be about 3 or so inches up from the bottom...).

A photo of your car without the grille fitted might help people to work out what your problem might be?

Cheers, Ian

I have an 88 Saloon 1000. I have no clear pics atm, but my front grille sits over the body between the bumper and the grille that is visible on your car. That is not supposed to be the case. I have no clue what sort of grille it is as it was the one that came with the car when I got it.

It's damaged anyway and will probably be replaced soon but I want to make sure the holes that have been drilled previously actually make sense for the grilles available.

Hello,
it might be helpful if you could tell us what year/model Mini you have and the parts that you are trying to fit (pictures would be even better).
There are several kids of grilles https://www.minimania.com/Search_Results/grille/Parts and some are made to fit 'modern Minis' (70s-90s to look like 60s),
cheers,
Abel

Here I am again with another post, sorry guys!

I have the following problem:
I ordered a new bonnet cover (the top part of the grille and that does not fit, as the part I received has 2 stops at the side making it so it doesn't fit my hood.

Next problem is with the grille itself, it does not sit flush at the bottom , it sticks out quite a lot at the bottom, the holes don't seem to line up and when I pulled the grille off it had 3 different types of screw, so it has been a headache refitting the old grille.
Is the grille supposed to stick out at the bottom? I see no way I will be able to get the brackets for the lamps in place like that.