No you dont take the 7.5 tonne test, tottally different thing that is.

You take your car to a lorry testing station and have them make sure its fit for towing etc and that the car is heavy enough to tow the desired trailer,
You cant tow more than 75% of your cars weight iirc,
They ask you to hook up a caravan and ask you various related questions along the way. You do a few manouveres in the test centre area where they asses weather your ok to go on the road,
Then you go out with the for about half hour whilst towing a caravan they supplied in my case You return to test centre, Get asked more towing related question, Then tell give you the good or bad news.

I didnt know until that point that if your car is permanent 4wd you can tow more weight,
Found this out later from a mate who works for envoironent agency as they were all being issued with Land rover 110's rather than the nissans they had been using

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