Prior to doing the M tuned coolant re route, I had an intermittant, strange rattle in what sounded like the passenger side dash. Quite loud and off putting.

After doing the reroute I have noticed it is more regular and now is on both sides. It turns out the bonnet appears to be rattling on each corner by the hinge and bolts.

If you tap the bonnet at each hinge you can hear something rattle or bang. I have checked the bolts (bonnet was removed for re route) and they are tight but something appears to be loose, any one have any suggestions as to what I have done wrong or what could be broken....?