Seen that kind of stupidity many times. I was particularly cross because I had no history on it so I checked the belt and it looked like new. It went just after I spent £200 changing the oil and filters and a set of gold palladium plugs because it was LPG yadda yadda.@julianthegypsy
the last transport manger were I worked, would only spend the minimum on the fleet vans. One Van The tensioner went. He only had that replaced, less than 400 miles later the belt went.
Van was sold as salvage. I think it went for £500 for a 4 year old van.
alternator clutch pulley.......................