Yeh just wondering about the lap belts really. I'm using the bolt holes for the rear seat belt buckles as ive seen people do this for the shoulder belts.
Hah, love the irony. So in asking where is the best place, you're decided to put them in one of the worst places
Not saying I'm a doctor who's seen loads of crushed spines from badly-installed harnesses, just passing on the info written by the proffesionals. Even if you do think FIA/MSA/whatever regs are "overkill" in anyway for "just" a few trackdays then 1) surely safety isn't the most sensible area to skimp on and 2) you can have just as bad a crash (decelleration/speed/injury wise) on your way to tesco or on a track day than if you were in high level motorsport.
EDIT: With regards to the "proper" way of doing the lapbelts (hole in floor, steel backing plates & high tensile* bolts) I'm sure there are better/worse places on the Clio's floor to be drilling through/mounting stuff on.
*Who knows how high a tensile strength you actually need. No doubt all the "high tensile" stuff on ebay etc is produced to no standards at all or the lowest "grade" needed to pass a BS/DIN/etc standard.