It’s synthetic, don’t use mineral based.
If you stick your van details in opie oils website and you’ll get some options. There’s a chat function and they can give an instant match without obligations.
I used Titan CHF 202 when flushing and renewing the oil.
My advice is NOT to follow those who have completely filled the reservoir, it isn’t required and as the oil warms up it needs to expand. If it can’t expand into the reservoir it will expand the hoses and may be pushed out through the seals.
You need to find the source of the leak, if nothing obvious or collecting in the undertray try putting a pin pr1ck in the lowest point on the steering rack gaitors. They should be dry.
I can’t believe the Forum spell checker won’t let me write PR1CK, WTF.