A is Coolant Pipe
B is Firewall Bulkhead panelling
The horizontal red line is the gap between the coolant pipe and the clip that holds the firewall panelling together
The solution is to force the clip further down (Indicated by red arrow) - This naturally increases the clearance between the coolant pipe and the bulkhead panelling. I just used a flat bladed screwdriver to force the clip further down.
Under hard acceleration the engines moves back and the clip has the potential to puncture a hole in that coolant pipe.
The location as you open your bonnet (hood if you are in the US) is back centre/left of engine bay by the rear bulkhead.