Let me respond to the below in parts
Hi - although I own one of the older Clio's (1994 to be exact and the bonnet open forward so little risk of it blowing up)
You are defo one of the lucky ones!
Can someone clearly say which catch is failing - is it the primary locking mechanism or the secondary safety catch - or is it both.
According to Renault - they don't know which - they blame both. But keep stating that both mechanisms are operated independently - what are the chances that both give way at the SAME TIME. Yep very slim - 0.01% I guess, if not less...now multiple this chance over 2000+ cases - hmmmm....that's a very unlucky and poor statistics of the fault!
In short, both catches are failing...
1) the safety (which is engaged first when you close it, and which is the one release with your hand underneath
the bonnet to push the lever) is not being engaged at all - i.e. stuck "open". This means the only catch that IS engaging is the main catch...read 2) This catch SHOULD NOT be called a safety catch - as it fails in its primary function, as it not engaged in all cases!
2) the main catch (which is the only you release through the passenger-cabin release lever), is engaging, but the risk of this not engaging fully is quite high it seems. This is the real issue, as the secondary/safety catch should only be "activated" if the main one fails or is not engaged fully!
In my past experience I have never seen a person close a bonnet as clearly recommended in the hand-book which says "Hold the bonnet about 9" (22cm) and let it drop onto its catch and then check it is secure".
Yeah I am glad you added some humour too because I stated the obvious to Renault HQ - stating that are you stating that non of the Renault customers can close a bonnet - they responded saying "closing a bonnet was straightforward", so I butted in and stated therefore the chances of someone not following the prescribed process if very rare then (it could happen, but that's the purpose of the safety catch - right?)
I am fairly certain the Clio problem has nothing to do with driver or whoever closed it last - but I've seen it happen on other vehicles were it was down to poor maintenace and incorrect closing procedures. Generally I find most bonnet catches on most cars to very poor - because if you were going to race or rally your grannies wee car the first thing scrutineers look for is an additional positive locking mechanism. I think that speaks for itself. Further comment would be appreciated.
Nope you are right, it is the design and manufacturing (parts used) of the mechanism. If you design something that is flimsy it will give...as in this example...
Now if you had your car door lock-mechanism made in the same material, not only would it open as you went around a roundabout, but people could easily break into your car