The challenge is, as someone said on another thread, with only 4 official jacking points the only truly approved way to lift the van is with a four point lift on those jacking points. Beyond that people are likely nervous of becoming the "definitive answer" in case the worst happens when people follow their suggestion.
The official jacking points are the 4 angle iron pieces highlighted in the
first post of this thread. You will need to use a jacking pad to protect it on a normal jack as it's designed mostly for the "hook" of a scissor jack.
The problem is with a single point jack on the jacking point there is no where to put an axle stand, and it is unsafe to work under a van with only a single thing stopping it falling on you. The best you can do is to take the weight on the jack on the jacking point and put an axle stand as DXX suggests on the body lower wishbone mount. On the rear the challenge is the anti roll bar, which is in the way and not strong enough to use instead. Someone else has posted a picture of a bottle jack and a stand
arranged very close together on a large block on the jack point. You need to decide if that is safe enough for you considering the place you have to work on your van and the tools you have.
If you are not comfortable with the safety of that there are places you can hire servicing bays with a four point lift such as:
Self Service Garage Oxford - Vehicle owners club based in Oxford. A self service garage with all the tools and equipment that you need - Car lifts Oxford
thisisyourgarage.com