Blowing hot and cold

Uneventful, enjoyable drive to Beaulieu until I hit slow moving traffic near Southampton. Water temperature crept up and the heater wasn't drawing as I used it to try to cool her down. Arrived safely at Beaulieu and parked the Jaguar on the stand. Checked under the bonnet and noticed a slight leak from a crack near the top hose joint on the radiator. Coolant level was still good, though.