Firstly I'd ask what use you are needing snatch recovery?
Occasionally it may be required, but really shouldn't be the first thought when recovering someone.
I would also highly recommend a proper kinetic rope (KERR) for any kind of snatch recovery. The 'stretch' in the rope makes them far kinder to recovery points and vehicle occupants. And will reduce the risk of recovery point failure.
As for the actual recovery points. The rear crossmember is a strong structural member attached to both chassis legs. It is the ideal place for a snatch recovery. Assuming you use a suitable rear spreader plate and high tensile nut & bolt fittings (min 8.8 or even 10.9). This location has been the primary recovery location for competition Land Rover's for 50 years+ and has proven to be very suitable.
A standard fit factory tow hitch should also be suitable. As long as it is fitted correctly, meaning on a Defender with the rear arms going to the chassis legs. A standard tow ball can be used, but is not really rated or designed for snatch recovery. Ensure the the actual hitch being used is suitable. I personally like the NATO hitch/pintle. But do make sure the locking pin is fitted when being used.
For competition use, a welded recovery point is not deemed safe or strong enough generally.