Just to be clear Nick17112, when you started the conversation, you were referring to caravans with an MTPLM of 1522, and as the others have said, its only just within the allowances of your licence. Your last post refers to caravans of 1300kg MTPLM which is a better match for the vehicle you mention, but you have moved the goalposts somewhat.
What is the kerbweight of your car. Its already been pointed out that "guidance" advises that your caravans MTPLM is around 85% of your cars kerbweight.
Unfortunately, there is much more to think about than the simple £3500kg figure that you are permitted, such as the 85% guidance, the cars maximum towing allowance, the weight that your towball can take (specified in the cars handbook), will the caravan meet that figure.
Nobody suggests that as Passat isnt a good tow vehicle because it is, but you must work within its cababilities and legally binding specifications. Exceeding that is not only foolhardy and dangerous, but would also likely invalidate your insurance.
Referring back to the 85% guidance, it is the advised target figure for a newbie, you can in theory go to 100% but you should never exceed that. As a new caravanner with a 100% ratio, i would suggest that combo would be foolish.
In short, if you want a large heavy caravan, then bite the bullet and take the test...................it isnt difficult.