Air Spring/Bag rear os suspension

I started up my Discovery for the first time in a while the other night, when i woke up in the morning the rear os seemed to have raised to its maximum height and would not return back down even after starting the engine. So i left it for another day and the next morning i woke and it had fallen to the bump stop, so i thought starting the engine would reset the suspension but this didnt happen, i heard noo hissing noises, but as i looked at the air spring/bag, it had seemed to have pop and was just there, like it had been ripped open,
any ideas on whether to replace the air spring/bag, or will this problem happen again?
please help
many thanks!

I'd replace the height sensors and the bags personally.

David Pye said:

I'd replace the height sensors and the bags personally.

Click to expand...

thank you, height sensors were replaced around 6 months ago though

Worth having a look at them and checking the linkages haven't broken in that case