Re: what would happen if a wrong cam belt kit was fitted?
1) An incoorst belt type wouldnt fit/ work, too long or short, or the wrong blocks - just wouldnt work
2) Mistimed? possibly but impossible to prove as blocks can jump and the belt stretch (see 3)
3) NOt tensioned correctly, again the tensioner if correct and the marker pointing the same way, it can still fail or go slack if faulty.
I am an independent engineer and would advise that it is almost impossible to prove negligence after this time(29000 miles)
If the inlet camshaft has taken a hit, it leads that the timing was out on one camshaft...this could be down to mistiming, but couls also be down to the variator failing, or the pulley bolts coming loose.
Either that or garage no.2 has damaged the camshaft removing the variator (in a vice or via the lobe locks) and is covering their ass.....