Janj and all, after seeing the video of the recovery, I'd like to share a personal experience I had recovering a stuck CJ-7, only that it had gotten stuck upfront in water & clay and all that created immense suction.
The suction plays a dirty part and conventional 'pull' doesnt help. We tried to recover it from an FJ, an LC 4.5, a 9000 lbs winch etc etc. Eventually a tractor was called in and that too on a pull alone did not set it free, it broke a recovery strap & a cable.
What we did in the end was a learning for us, 2 people on each side of the CJ started to rock it side by side while the tractor pulled. The rocking motion broke the suction hold and it came out fairly easy.
Here's what the stuck jeep look like.

