Hello everyone bought a Skoda fabia 1.4 16v 2005 nice car the problem is I need the change the inner panel but i dont want to put rivets back in i want to put m10 bolts in but need to the length of the blots Thanks 

You can't use bolts, you have to use rivets, early cars had nutserts for the bolts to screw into, yours doesn't.

Just done this on mine. Either you will have to get the proper Skoda rivets and a suitable rivet tool. Or you could use M6 rivnuts. But will have to drill the whole for them to fit. Personally I'd just rivet it back on. 

Was thinking of doing that but When i opened it someone already drilled them out and put in bolts but i lost them 

Then 10mm bolts should be long enough if suitable nutserts are already in.