Not faulty water pump, but busted overflow tank...?

Lads I have confirmed its not a faulty water pump but when I fill the coolant reserver to the lip, over the reccommended FULL mark , it starts spilling out of the water reservoir in the passenger front wing...? is this normal cause Ive never seen this reservoir before (never had the wing off to see it) Does anyone know is that is normal for water to flow out of the water reservoir in the front passenger side wing

Im getting it pressure tested in the morning so hopefully it will come good, :dunno: hopefully