The first picture depics the seepage as the result of a cold block test using the bdm block tester. If you notice it is very little and hardly noticable.
The second picture depics the seepage as the result after the block water has been thoroughly heated. The method John and Greg have come up with uses a burner and the block tester to circulate hot water through the block, which mimics actual engine temps. You can notice this seepage alot more. This picture does not do it justice the water will actually shoot out of the sleeve.
Black Dog Manufacturing has put together a kit that will help diagnose a coolant leak on a Land Rover engine block. The Rover Block Leak Tester is made to identify any leaks that the block may have, allowing the technician to be 100% sure of what the problem is, all while the engine is still on the vehicle. These tester are for the following Land Rover models Discovery 1 (1994-1999), Discovery 2 (1999-2004) and Range Rover (1995-2002).