Should I avoid a Ford Transit that has intermittent black smoke from the exhaust?

I'm looking at buying a Ford Transit Mk6 with 68K on the clock for £6k. Partially converted camper. All is well except intermittent black smoke. The owner says he has changed filters and been to two separate...

Why is the classification of vans so confusing?

I am looking to buy a facelifted 2025 Citroen Berlingo either petrol or diesel, but the vehicle classifications are maddeningly confusing. Seemingly identical vehicles are either classed as M1 (i.e a car)...