Check the small pipe that goes from the top of the rad to the expansion tank👍 The cap on the expansion tank can give up as well but then the coolant would run towards the bulkhead🤔

Check the overflow pipe from the coolant tank in case it's pressurising and blowing out.

All the hoses and then the rad itself. Given that there's coolant in the battery tray the little hose from the rad to the expansion tank would be worth looking at first. You can get UV dye to go in the coolant to help track leaks.

My P38 2.5 Diesel Auto (MY2000) has recently been leaking coolant. Vehicle has still been driving as normal, temperature gauge remains within the ideal zones. After driving coolant was dripping out from under front bumper on the right hand side...