If no profile is marked then it used to be 82.5% rather than 80, however both are now 80
More to the point though, if not showing 80 then the load index will be slightly less, so putting in the 80 will give you the correct size tyre but with a better load index number.
One more thing is, most van manufactures fit the bare minimum tyre they can, it is best practice to fit tyres that can carry 10% more than the van weighs.
So add 10% to your vans weight and choose a tyre of the same size but with a load index to suit.
I've just had 2 fitted by etyres, slightly more expensive than competitors but no hassle, they just came to the house and wacked them on, however!! one reason for choosing them is that they did Tyron bands and i was unsure if mine had them, it turns out they were not fitted, if they were he was going to charge an extra £10/wheel !!
The cheapest place I've found for supply only is www.camskill.co.uk I got my OH's tyres from there with next day delivery.