Your coolant leak at the back side of the engine is most likely coming from the valley pan portion of the intake manifold, pretty common and not too hard to replace.
If the t/body heater system is leaking, you can get an updated repair kit for around $35 or so US.
Have someone pressure test the coolant system to confirm the leak and then get it fixed ASAP so you don't damage the engine.

Mike

 

Thanks Mike. The leak is actually right behind the bumper, underneath the radiator. I have to take a closer look. What is the life expectancy of a radiator on a disco II? Do you suggest adding any leak stop for now? I keep checking the levels and it isn't leaking that bad yet.