They're right about the OBD-II - it is typically affixed to the car, frequently on the upper right hand side of the drivers' foot well. This is the case with the Disco. However I think it's a REAL stretch that they'd fail you for a loose connector. Emission tests are meant to check the overall safety features of the vehicle (lights, horns, tires, brakes) and ensure that the pollution-prevention systems in the car are in good order. A loose OBD-II connector has nothing to do with either of these.
If they charged you for a failed test - I'd ask to speak to the manager of the testing location and ask him to show me where in the rule book does it say that the plug must be fixed to the car. Odds are he won't be able to provide such info.
I'm not positive on how the plug is actually attached to our dash (i think it should just clip in to a bracket) but if you can't figure it out or if your mounting hardware is broken a creative use of zip-ties or commercial strength Velcro should be able to get the plug cinched up enough for you to pass.
If they charged you for a failed test - I'd ask to speak to the manager of the testing location and ask him to show me where in the rule book does it say that the plug must be fixed to the car. Odds are he won't be able to provide such info.
I'm not positive on how the plug is actually attached to our dash (i think it should just clip in to a bracket) but if you can't figure it out or if your mounting hardware is broken a creative use of zip-ties or commercial strength Velcro should be able to get the plug cinched up enough for you to pass.