It'll be a T Pole chassis supplied by ALKO or BPW. Like this :-

g7p1994-Framework-separated.html

It should be marked, ours is (ALKO). The plate is on the right hand side of the rectangular box section when viewed from the front and is positioned just at the point the box section disappears under the van. As your van will have a fairing you'll have to scrabble around to find it somewhere behind the jockey wheel. (I'm not sure if I read somewhere that ALKO supplied chassis are rectangular section and BPW are round? Don't quote me on that).

Randa