Heat shield rattle

Getting a rattle from the rear heat shield, whats the best way to secure it? Will I need to remove the diffuser to get at it?
 
Mines at Renault getting it sorted so I'll try and find out what they do to sort it.

They did mention having to remove the diffuser...
 
The car is still at Renault but they have confirmed they have re-bonded the heat shield to the diffuser so it must of come away a bit.