My Transit Custom has a wet belt. The Van will be 5 years old in November, I will arrange to have the belt changed, as not taking any risks, the oil has been changed every year using the correct Castrol Magnatec oil. Talking to a Mechanic mate, he thinks it is a ridiculous design, but did say if you change the oil at the correct time, using a decent oil, you will be fine. If your vehicle flashes on with a 'Regen light' get the Regen done as soon as possible, as this does dilute the oil. Most newer vehicles will self Regen.
Will update when the Belt is renewed
Thanks