Disco 3 lock air suspension

Hello

I have a disco 3 2009 diesel with air suspension I need to do some work on it with the air suspension in the highest height. I don’t want to risk the car dropping if it lets go the air. Is there a way to lock it at this height so it is safe. I have not got to crawl under or anything but want to be sure it stays up

Thanks

Hi. Use axle stands or jacks if you want to be 100% safe cos you can't rely on some valves ... disconnecting the battery should let it where it is at that moment cos there's no power for the valve block