Land Rover Repair: LR3 Coolant Issue, coolant loss, coolant tank

Question
I have a 2007 LR3 V8SE.  The Low Coolant Warning came on. Took it to the dealer and they replaced the tank and sensor.  Warning came on again about a month later and I checked the level. It was almost empty. I refilled the tank and one week later the warning came on again. Went back to the dealer to have them check for any leakage. There was none. Not sure what the problem could be but I know I shouldn't be filling the coolant tank once a week - not good.  Need to go back to the dealer but do you have any ideas what this could be? Thermostat related possibly?  I also keep getting the amber suspension fault light even after the suspension has been lowered to normal drive use - it switches back about 5 min after driving and the warning stays illuminated.  Doubt these are related, but I don't want to take it to the dealer without any knowledge of what could be wrong.  Thanks!

Answer
On the coolant loss . . . A pressure test (hot and cold) should reveal the source of coolant loss.  If you have to add coolant every week there IS a leak.  If on the other hand the light just comes on but coolant is not low you have a different problem.  You need to be clear which situation is occurring.

The suspension warning is almost certainly unrelated and there is no single thing to look for,

Best of luck in resolving this.  It should be straightforward.